App logs, client settings, NavMenu layout

- Add real-time app logs via SignalR (log level, category filters)
- Add filters modal with restore defaults; sentinel for empty arrays
- Add client settings: max lines and auto-scroll per log panel
- Improve NavMenu: align settings + hamburger, smaller mobile logo
- LogsService, LogsHub, LoggingController, AppLogsLoggerProvider
- Persist log level and filters to appsettings.Overrides.json

.github/workflows/release.yml

@@ -29,14 +29,14 @@ jobs:
         run: |
           docker run --rm \
             -v "${{ github.workspace }}:/src" -w /src \
-            mcr.microsoft.com/dotnet/sdk:9.0 \
+            mcr.microsoft.com/dotnet/sdk:10.0 \
             ./scripts/publish-self-contained.sh ${{ matrix.rid }}
 
       - name: Setup .NET
         if: matrix.rid == 'linux-musl-x64' || matrix.rid == 'linux-musl-arm64'
         uses: actions/setup-dotnet@v4
         with:
-          dotnet-version: '9.0.x'
+          dotnet-version: '10.0.x'
 
       - name: Publish for ${{ matrix.rid }} (musl on host)
         if: matrix.rid == 'linux-musl-x64' || matrix.rid == 'linux-musl-arm64'
@@ -44,7 +44,7 @@ jobs:
 
       - name: Zip publish output
         run: |
-          PUBLISH_DIR="src/DnsmasqWebUI/bin/Release/net9.0/${{ matrix.rid }}/publish"
+          PUBLISH_DIR="src/DnsmasqWebUI/bin/Release/net10.0/${{ matrix.rid }}/publish"
           (cd "$PUBLISH_DIR" && zip -r "../../../../../../../dnsmasq-webui-${{ matrix.rid }}.zip" .)
 
       - name: Upload artifact

.gitignore

@@ -43,6 +43,7 @@ testdata-mount/
 .DS_Store
 Thumbs.db
 
-# User-specific
+# User-specific / runtime
 appsettings.*.local.json
+appsettings.Overrides.json
 *.local

Dockerfile

@@ -3,12 +3,12 @@
 # For dnsmasq on the host, use the self-contained publish (scripts/publish-self-contained.sh)
 # or run the app on the host; see DnsmasqOptions XML doc for permissions and ReloadCommand scope.
 
-FROM mcr.microsoft.com/dotnet/aspnet:9.0 AS base
+FROM mcr.microsoft.com/dotnet/aspnet:10.0 AS base
 WORKDIR /app
 EXPOSE 8080
 EXPOSE 8081
 
-FROM mcr.microsoft.com/dotnet/sdk:9.0 AS build
+FROM mcr.microsoft.com/dotnet/sdk:10.0 AS build
 WORKDIR /src
 COPY ["src/DnsmasqWebUI/DnsmasqWebUI.csproj", "src/DnsmasqWebUI/"]
 RUN dotnet restore "src/DnsmasqWebUI/DnsmasqWebUI.csproj"

README.md

@@ -385,7 +385,7 @@ sudo ./scripts/install.sh --uninstall --purge --system
 ./scripts/publish-self-contained.sh --no-clean ubuntu.24.04-x64
 ```
 
-**Output:** `src/DnsmasqWebUI/bin/Release/net9.0/<RID>/publish/`
+**Output:** `src/DnsmasqWebUI/bin/Release/net10.0/<RID>/publish/`
 
 ---
 

docker-compose.test.yml

@@ -26,6 +26,8 @@ services:
       # Simulated systemctl status + real logs (dnsmasq logs to /data/dnsmasq.log via log-facility in dnsmasq-test.conf)
       Dnsmasq__StatusShowCommand: "/app/dnsmasq-status.sh"
       Dnsmasq__LogsCommand: "tail -n 100 /data/dnsmasq.log 2>/dev/null || echo '(no log file yet)'"
+      # Persist runtime log level across container restarts
+      RuntimeOverrides__FilePath: "/data/appsettings.Overrides.json"
     volumes:
       - ${TESTDATA_MOUNT:-./testdata-mount}:/data
     networks:

scripts/install.sh

@@ -346,7 +346,7 @@ do_install_from_source() {
     exit 1
   fi
   if ! command -v dotnet >/dev/null 2>&1; then
-    echo "Error: --build-from-source requires the .NET SDK. Install from https://dotnet.microsoft.com/download or your distro (e.g. apt install dotnet-sdk-9.0)." >&2
+    echo "Error: --build-from-source requires the .NET SDK. Install from https://dotnet.microsoft.com/download or your distro (e.g. apt install dotnet-sdk-10.0)." >&2
     exit 1
   fi
 
@@ -371,7 +371,7 @@ do_install_from_source() {
     echo "Error: Could not determine RID from build output." >&2
     exit 1
   fi
-  publish_dir="$repo_root/src/DnsmasqWebUI/bin/Release/net9.0/$rid/publish"
+  publish_dir="$repo_root/src/DnsmasqWebUI/bin/Release/net10.0/$rid/publish"
   if [ ! -d "$publish_dir" ] || [ ! -f "$publish_dir/DnsmasqWebUI" ]; then
     echo "Error: Build output not found at $publish_dir" >&2
     exit 1

scripts/prepare-test-mount.sh

@@ -3,7 +3,7 @@
 # (app + dnsmasq + DHCP client). See testdata/README.md and docker-compose.test.yml.
 #
 # What this script does:
-#   Start (default): clear mount (unless --no-clear), sync source -> mount, clean up previous test data,
+#   Start (default): sync source -> mount (preserving existing unless --clear), clean up previous test data,
 #     then docker compose up -d [--build] [--force-recreate].
 #   --stop: docker compose down (stop and remove containers/networks).
 #   --tidy: docker compose down, then clear the mount directory for a clean next run.
@@ -18,7 +18,7 @@ MOUNT_DIR=""
 PREPARE_ONLY=false
 BUILD=false
 RECREATE=false
-NO_CLEAR=false
+CLEAR=false
 STOP=false
 TIDY=false
 
@@ -26,10 +26,10 @@ usage() {
   echo "Usage: $0 [OPTIONS] [--]"
   echo ""
   echo "Prepare the testdata mount directory and optionally start or stop the Docker test harness"
-  echo "(app + dnsmasq + DHCP client). By default: clear mount, sync testdata -> mount, then up -d (no rebuild)."
+  echo "(app + dnsmasq + DHCP client). By default: sync testdata -> mount (preserving existing), then up -d (no rebuild)."
   echo ""
   echo "Steps (when starting):"
-  echo "  1. Clear mount dir (unless --no-clear), then sync source -> mount."
+  echo "  1. Optionally clear mount dir (only with --clear), then sync source -> mount."
   echo "  2. Clean up previous test data (e.g. managed config) so the harness starts clean."
   echo "  3. If not --prepare-only: docker compose -f $COMPOSE_FILE up -d [options]."
   echo ""
@@ -39,9 +39,8 @@ usage() {
   echo "                      Compose uses TESTDATA_MOUNT; script exports it if you use --mount."
   echo ""
   echo "Mount behaviour:"
-  echo "  (default)           Clear mount dir completely, then sync. Use for a clean run."
-  echo "  --no-clear          Do not clear mount dir; only sync over existing contents."
-  echo "                      Use to preserve leases or debug files between runs."
+  echo "  (default)           Preserve mount dir; sync source over existing contents."
+  echo "  --clear             Clear mount dir completely before sync. Use for a clean run."
   echo ""
   echo "Compose behaviour:"
   echo "  --prepare-only      Only prepare the mount; do not run docker compose."
@@ -62,19 +61,19 @@ usage() {
   echo ""
   echo "Examples:"
   echo "  $0"
-  echo "                      Full run: clear mount, sync testdata, start containers (no rebuild)."
+  echo "                      Sync testdata to mount (preserving existing), start containers (no rebuild)."
   echo ""
   echo "  $0 --build"
-  echo "                      Clear and sync, then rebuild images and start containers."
+  echo "                      Sync, rebuild images, and start containers."
   echo ""
   echo "  $0 --recreate"
-  echo "                      Clear and sync, then up -d --force-recreate (fresh containers)."
+  echo "                      Sync, then up -d --force-recreate (fresh containers)."
   echo ""
-  echo "  $0 --no-clear"
-  echo "                      Preserve mount contents, sync over it, start (no rebuild)."
+  echo "  $0 --clear"
+  echo "                      Clear mount, sync testdata, start (clean run, no rebuild)."
   echo ""
   echo "  $0 --prepare-only"
-  echo "                      Only clear and sync testdata -> testdata-mount; no containers."
+  echo "                      Only sync testdata -> testdata-mount; no containers."
   echo "                      Then run: docker compose -f $COMPOSE_FILE up -d [--build]"
   echo ""
   echo "  $0 --source myfixtures --mount mymount --prepare-only"
@@ -106,8 +105,8 @@ while [ $# -gt 0 ]; do
       MOUNT_DIR="$1"
       shift
       ;;
-    --no-clear)
-      NO_CLEAR=true
+    --clear)
+      CLEAR=true
       shift
       ;;
     --prepare-only)
@@ -189,7 +188,7 @@ docker compose -f "$COMPOSE_FILE" down
 
 mkdir -p "$MOUNT_DIR"
 
-if [ "$NO_CLEAR" = false ]; then
+if [ "$CLEAR" = true ]; then
   echo "Clearing mount directory: $MOUNT_DIR"
   find "$MOUNT_DIR" -mindepth 1 -delete 2>/dev/null || true
 fi

scripts/publish-self-contained.sh

@@ -85,7 +85,7 @@ while [ $# -gt 0 ]; do
       echo "    ubuntu.24.04-x64   ubuntu.24.04-arm64"
       echo "    ubuntu.22.04-x64   ubuntu.22.04-arm64"
       echo ""
-      echo "Output: src/DnsmasqWebUI/bin/Release/net9.0/<RID>/publish/"
+      echo "Output: src/DnsmasqWebUI/bin/Release/net10.0/<RID>/publish/"
       echo ""
       echo "Examples:"
       echo "  $0                          # Publish for current machine (auto-detect RID)"
@@ -163,7 +163,7 @@ else
     --self-contained true
 fi
 
-OUT_DIR="$REPO_ROOT/src/DnsmasqWebUI/bin/Release/net9.0/$RID/publish"
+OUT_DIR="$REPO_ROOT/src/DnsmasqWebUI/bin/Release/net10.0/$RID/publish"
 echo ""
 echo "Done. Output: $OUT_DIR"
 echo "Run on this host:    $OUT_DIR/DnsmasqWebUI"

src/DnsmasqWebUI.Tests/DnsmasqWebUI.Tests.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk">
 
   <PropertyGroup>
-    <TargetFramework>net9.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <ImplicitUsings>enable</ImplicitUsings>
     <Nullable>enable</Nullable>
     <IsPackable>false</IsPackable>

src/DnsmasqWebUI/Components/Dnsmasq/AppLogsFiltersModal.razor

@@ -0,0 +1,46 @@
+@namespace DnsmasqWebUI.Components.Dnsmasq
+@inject ILoggingClient LoggingClient
+@inject IJSRuntime JSRuntime
+@implements IAsyncDisposable
+
+@if (IsVisible)
+{
+    <dialog @ref="_dialogRef" class="settings-modal-dialog">
+        <div class="modal-content">
+            <div class="modal-header">
+                <h5 class="modal-title">App logs filters</h5>
+                <button type="button" class="btn-close" @onclick="Close" aria-label="Close"></button>
+            </div>
+            <div class="modal-body">
+                <p class="text-muted small mb-2">Logger categories matching these prefixes are excluded from the app logs display.</p>
+                <div class="input-group input-group-sm mb-2">
+                    <input type="text" class="form-control" placeholder="e.g. Microsoft.AspNetCore."
+                           @bind="_newPrefix" @bind:event="oninput" @onkeydown="OnNewPrefixKeydown" />
+                    <button type="button" class="btn btn-outline-primary" @onclick="AddPrefix" disabled="@string.IsNullOrWhiteSpace(_newPrefix)">Add</button>
+                </div>
+                <ul class="list-group list-group-flush" style="max-height: 12rem; overflow-y: auto;">
+                    @foreach (var prefix in _prefixes)
+                    {
+                        <li class="list-group-item d-flex align-items-center justify-content-between py-1 px-2">
+                            <code class="small text-break">@prefix</code>
+                            <button type="button" class="btn btn-link btn-sm p-0 text-danger" aria-label="Remove" @onclick="() => RemovePrefix(prefix)">
+                                <i class="bi bi-x-lg" aria-hidden="true"></i>
+                            </button>
+                        </li>
+                    }
+                    @if (_prefixes.Count == 0)
+                    {
+                        <li class="list-group-item text-muted small py-2">No filters. All categories are shown.</li>
+                    }
+                </ul>
+            </div>
+            <div class="modal-footer d-flex justify-content-between align-items-center">
+                <button type="button" class="btn btn-secondary" @onclick="RestoreDefaults" disabled="@_saving">Restore defaults</button>
+                <div>
+                    <button type="button" class="btn btn-secondary" @onclick="Close">Cancel</button>
+                    <button type="button" class="btn btn-primary" @onclick="Save" disabled="@_saving">@(_saving ? "Saving…" : "Save")</button>
+                </div>
+            </div>
+        </div>
+    </dialog>
+}

src/DnsmasqWebUI/Components/Dnsmasq/AppLogsFiltersModal.razor.cs

@@ -0,0 +1,154 @@
+using DnsmasqWebUI.Infrastructure.Client.Abstractions;
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.Components.Web;
+using Microsoft.JSInterop;
+
+namespace DnsmasqWebUI.Components.Dnsmasq;
+
+public partial class AppLogsFiltersModal : IAsyncDisposable
+{
+    private ElementReference _dialogRef;
+    private IJSObjectReference? _jsModule;
+    private DotNetObjectReference<AppLogsFiltersModal>? _dotNetRef;
+    private List<string> _prefixes = [];
+    private List<string> _originalPrefixes = [];
+    private string _newPrefix = string.Empty;
+    private bool _saving;
+    private bool _moduleLoaded;
+    private bool _dialogInitialized;
+    private bool _wasVisible;
+    private readonly CancellationTokenSource _cts = new();
+
+    [Parameter] public bool IsVisible { get; set; }
+
+    [Parameter] public EventCallback OnClose { get; set; }
+
+    [JSInvokable]
+    public async Task OnDialogClosed(string returnValue)
+    {
+        await OnClose.InvokeAsync();
+    }
+
+    protected override async Task OnParametersSetAsync()
+    {
+        var justOpened = IsVisible && !_wasVisible;
+        _wasVisible = IsVisible;
+        if (justOpened)
+        {
+            _dialogInitialized = false;
+            try
+            {
+                var filters = await LoggingClient.GetFiltersAsync(_cts.Token);
+                _prefixes = filters.ToList();
+                _originalPrefixes = filters.ToList();
+            }
+            catch (OperationCanceledException) { }
+            catch { /* leave current */ }
+        }
+    }
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (firstRender)
+        {
+            try
+            {
+                _jsModule = await JSRuntime.InvokeAsync<IJSObjectReference>("import", "./js/settings-modal.js");
+                _dotNetRef = DotNetObjectReference.Create(this);
+                _moduleLoaded = true;
+            }
+            catch (InvalidOperationException) { }
+            catch (JSDisconnectedException) { }
+            catch (JSException) { }
+        }
+
+        if (IsVisible && _moduleLoaded && _jsModule != null)
+        {
+            if (!_dialogInitialized)
+            {
+                await _jsModule.InvokeVoidAsync("initDialog", _dialogRef, _dotNetRef);
+                _dialogInitialized = true;
+            }
+            await _jsModule.InvokeVoidAsync("showModal", _dialogRef);
+        }
+    }
+
+    private async Task Close()
+    {
+        if (_jsModule != null)
+            await _jsModule.InvokeVoidAsync("closeModal", _dialogRef);
+        await OnClose.InvokeAsync();
+    }
+
+    private void AddPrefix()
+    {
+        var p = _newPrefix?.Trim();
+        if (string.IsNullOrEmpty(p) || _prefixes.Contains(p, StringComparer.Ordinal)) return;
+        _prefixes.Add(p);
+        _newPrefix = string.Empty;
+    }
+
+    private void RemovePrefix(string prefix)
+    {
+        _prefixes.Remove(prefix);
+    }
+
+    private void OnNewPrefixKeydown(KeyboardEventArgs e)
+    {
+        if (e.Key == "Enter")
+        {
+            AddPrefix();
+        }
+    }
+
+    private async Task Save()
+    {
+        _saving = true;
+        StateHasChanged();
+        try
+        {
+            await LoggingClient.SetFiltersAsync(_prefixes, _cts.Token);
+            _originalPrefixes = [.. _prefixes];
+            await Close();
+        }
+        catch (OperationCanceledException) { }
+        catch { /* leave modal open */ }
+        finally
+        {
+            _saving = false;
+            StateHasChanged();
+        }
+    }
+
+    private async Task RestoreDefaults()
+    {
+        _saving = true;
+        StateHasChanged();
+        try
+        {
+            var defaults = await LoggingClient.RestoreFilterDefaultsAsync(_cts.Token);
+            _prefixes = defaults.ToList();
+            _originalPrefixes = [.. _prefixes];
+            await Close();
+        }
+        catch (OperationCanceledException) { }
+        catch { /* leave modal open */ }
+        finally
+        {
+            _saving = false;
+            StateHasChanged();
+        }
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        _cts.Cancel();
+        _cts.Dispose();
+        _dotNetRef?.Dispose();
+        if (_jsModule != null)
+        {
+            try { await _jsModule.DisposeAsync(); }
+            catch { /* ignore */ }
+        }
+    }
+}

src/DnsmasqWebUI/Components/Dnsmasq/AppLogsFiltersModal.razor.css

@@ -0,0 +1,47 @@
+/* App logs filters modal – scoped styles; root is the dialog */
+.settings-modal-dialog {
+    border: none;
+    border-radius: 0.5rem;
+    padding: 0;
+    box-shadow: 0 0.5rem 2rem rgba(0, 0, 0, 0.2);
+}
+
+.settings-modal-dialog::backdrop {
+    background: rgba(0, 0, 0, 0.5);
+}
+
+.modal-content {
+    max-width: 28rem;
+    margin: auto;
+}
+
+.modal-header {
+    padding: 1rem 1.25rem;
+    border-bottom: 1px solid rgba(0, 0, 0, 0.08);
+}
+
+.modal-title {
+    margin: 0;
+    font-size: 1.25rem;
+}
+
+.modal-body {
+    padding: 1.25rem;
+}
+
+.modal-footer {
+    display: flex;
+    flex-wrap: wrap;
+    justify-content: flex-end;
+    align-items: center;
+    gap: 0.75rem;
+    padding: 1rem 1.25rem;
+    border-top: 1px solid rgba(0, 0, 0, 0.08);
+}
+
+.modal-footer .btn {
+    min-width: 4.5rem;
+    padding: 0.5rem 1rem;
+    border-radius: 0.375rem;
+    font-weight: 500;
+}

src/DnsmasqWebUI/Components/Dnsmasq/AppLogsSection.razor

@@ -0,0 +1,33 @@
+@namespace DnsmasqWebUI.Components.Dnsmasq
+@* App logs — live view via SignalR from ILogger *@
+@using DnsmasqWebUI.Models.Logs
+@using Microsoft.AspNetCore.SignalR.Client
+@inject NavigationManager Navigation
+@inject IJSRuntime JSRuntime
+@inject ILogger<AppLogsSection> Logger
+@implements IAsyncDisposable
+
+<p class="mb-1 mt-3 d-flex align-items-center justify-content-between flex-wrap gap-1">
+    <span class="d-flex align-items-center gap-1 flex-wrap">
+        <strong>App logs</strong>
+        <span class="status-dot d-inline-block rounded-circle flex-shrink-0 bg-success @(_justUpdated ? "status-dot-updating" : null)" style="width: 0.5rem; height: 0.5rem;" title="@(_justUpdated ? "Updating…" : "Live")" aria-hidden="true"></span>
+    </span>
+    <span class="d-flex align-items-center gap-1 flex-wrap">
+        <select class="form-select form-select-sm" style="width: auto;" aria-label="Log level" @bind="_logLevel" @bind:after="OnLogLevelChanged" disabled="@_logLevelDisabled">
+            <option value="Trace">Trace</option>
+            <option value="Debug">Debug</option>
+            <option value="Information">Information</option>
+            <option value="Warning">Warning</option>
+            <option value="Error">Error</option>
+            <option value="Critical">Critical</option>
+        </select>
+        <button type="button" class="btn btn-link btn-sm p-0 text-body" aria-label="App logs category filters" @onclick="OpenFiltersModal" title="Configure category filters">
+            <i class="bi bi-funnel-fill bi-gear-sm" aria-hidden="true"></i>
+        </button>
+        <button type="button" class="btn btn-link btn-sm p-0 text-body" aria-label="App logs polling settings" @onclick="() => OnOpenSettings.InvokeAsync()" title="Configure app logs polling interval">
+            <i class="bi bi-gear-fill bi-gear-sm" aria-hidden="true"></i>
+        </button>
+    </span>
+</p>
+<AppLogsFiltersModal IsVisible="_filtersModalVisible" OnClose="CloseFiltersModal" />
+<pre id="app-logs-pre" class="pre-block mb-0" style="max-height: 24rem;">@_initialPlaceholder</pre>

src/DnsmasqWebUI/Components/Dnsmasq/AppLogsSection.razor.cs

@@ -0,0 +1,195 @@
+using DnsmasqWebUI.Infrastructure.Client.Abstractions;
+using DnsmasqWebUI.Models.Client;
+using DnsmasqWebUI.Models.Logs;
+using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.SignalR.Client;
+using Microsoft.JSInterop;
+
+namespace DnsmasqWebUI.Components.Dnsmasq;
+
+/// <summary>
+/// App logs block: connects to LogsHub, receives AppLogsUpdate pushes, polls at interval as fallback.
+/// Snapshot on connect; RequestAppLogsUpdate on poll. Log level is configurable at runtime (persisted to appsettings.Overrides.json).
+/// </summary>
+public partial class AppLogsSection : IAsyncDisposable
+{
+    private const string AppLogsPreId = "app-logs-pre";
+
+    [Inject] private ILoggingClient LoggingClient { get; set; } = null!;
+
+    private bool _justUpdated;
+    private int _intervalSeconds;
+    private string _logLevel = "Information";
+    private bool _logLevelDisabled;
+    private bool _filtersModalVisible;
+    private HubConnection? _hubConnection;
+    private IJSObjectReference? _logsJs;
+    private Timer? _pollTimer;
+    private Timer? _justUpdatedResetTimer;
+    private readonly CancellationTokenSource _cts = new();
+
+    [Parameter] public int RefreshIntervalSeconds { get; set; } = 15;
+
+    [Parameter] public int LogsMaxLines { get; set; } = 500;
+
+    [Parameter] public bool LogsAutoScroll { get; set; } = true;
+
+    [Parameter] public EventCallback OnOpenSettings { get; set; }
+
+    private string _initialPlaceholder => _hubConnection?.State == HubConnectionState.Connected ? "Waiting for logs…" : "Connecting…";
+
+    private object LogsOptions => new { maxLines = LogsMaxLines, autoScroll = LogsAutoScroll };
+
+    protected override void OnParametersSet()
+    {
+        var next = ClientSettingsFields.AppLogsPollingInterval.Clamp(RefreshIntervalSeconds);
+        if (next == _intervalSeconds) return;
+        _intervalSeconds = next;
+        RestartPollTimer();
+    }
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (!firstRender) return;
+        _intervalSeconds = ClientSettingsFields.AppLogsPollingInterval.Clamp(RefreshIntervalSeconds);
+        var hubUri = new Uri(new Uri(Navigation.BaseUri), "hubs/logs").ToString();
+
+        _hubConnection = new HubConnectionBuilder()
+            .WithUrl(hubUri)
+            .WithAutomaticReconnect()
+            .Build();
+
+        _hubConnection.On<LogsUpdatePayload>("AppLogsUpdate", OnAppLogsUpdate);
+
+        try
+        {
+            _logsJs = await JSRuntime.InvokeAsync<IJSObjectReference>("import", "./js/logs.js");
+        }
+        catch (InvalidOperationException ex) { Logger.LogDebug(ex, "AppLogsSection: JS import skipped (prerender)"); return; }
+        catch (JSDisconnectedException ex) { Logger.LogDebug(ex, "AppLogsSection: JS import skipped (circuit disconnected)"); return; }
+        catch (JSException ex) { Logger.LogDebug(ex, "AppLogsSection: JS import failed"); return; }
+
+        await _hubConnection.StartAsync(_cts.Token);
+        RestartPollTimer();
+
+        try
+        {
+            _logLevel = await LoggingClient.GetLevelAsync(_cts.Token);
+        }
+        catch (OperationCanceledException) { }
+        catch (Exception) { /* leave default */ }
+
+        // Request initial snapshot (replace)
+        try
+        {
+            await _hubConnection.InvokeAsync("RequestAppLogsSnapshot", _cts.Token);
+        }
+        catch (OperationCanceledException) { }
+        catch (Exception) { /* ignore */ }
+    }
+
+    private void OpenFiltersModal() => _filtersModalVisible = true;
+    private void CloseFiltersModal() => _filtersModalVisible = false;
+
+    private async Task OnLogLevelChanged()
+    {
+        if (string.IsNullOrEmpty(_logLevel)) return;
+        _logLevelDisabled = true;
+        try
+        {
+            var updated = await LoggingClient.SetLevelAsync(_logLevel, _cts.Token);
+            _logLevel = updated;
+        }
+        catch (OperationCanceledException) { }
+        catch (Exception) { /* leave binding as-is */ }
+        finally
+        {
+            _logLevelDisabled = false;
+            StateHasChanged();
+        }
+    }
+
+    private void RestartPollTimer()
+    {
+        _pollTimer?.Dispose();
+        _pollTimer = new Timer(
+            _ => _ = InvokeAsync(PollTick),
+            null,
+            TimeSpan.FromSeconds(_intervalSeconds),
+            TimeSpan.FromSeconds(_intervalSeconds));
+    }
+
+    private async Task PollTick()
+    {
+        if (_cts.Token.IsCancellationRequested || _hubConnection?.State != HubConnectionState.Connected)
+            return;
+        try
+        {
+            await _hubConnection.InvokeAsync("RequestAppLogsUpdate", _cts.Token);
+        }
+        catch (OperationCanceledException) { }
+        catch (Exception) { /* ignore */ }
+    }
+
+    private async void OnAppLogsUpdate(LogsUpdatePayload payload)
+    {
+        try
+        {
+            await InvokeAsync(async () =>
+            {
+                if (_logsJs == null) return;
+                try
+                {
+                    if (payload.Mode == "replace")
+                        await _logsJs.InvokeVoidAsync("replaceLogs", AppLogsPreId, payload.Content, LogsOptions);
+                    else
+                        await _logsJs.InvokeVoidAsync("appendLogs", AppLogsPreId, payload.Content, LogsOptions);
+                    SetJustUpdated();
+                    StateHasChanged();
+                }
+                catch (JSDisconnectedException) { /* Circuit disconnected; ignore */ }
+                catch (InvalidOperationException) { /* Prerender or circuit disposed; ignore */ }
+                catch (JSException) { /* JS error; ignore */ }
+            });
+        }
+        catch (ObjectDisposedException) { /* Component disposed; ignore */ }
+        catch (InvalidOperationException) { /* Circuit disconnected; ignore */ }
+    }
+
+    private void SetJustUpdated()
+    {
+        _justUpdated = true;
+        _justUpdatedResetTimer?.Dispose();
+        _justUpdatedResetTimer = new Timer(_ =>
+        {
+            _justUpdatedResetTimer?.Dispose();
+            _justUpdatedResetTimer = null;
+            _ = InvokeAsync(() =>
+            {
+                _justUpdated = false;
+                StateHasChanged();
+            });
+        }, null, TimeSpan.FromSeconds(2), Timeout.InfiniteTimeSpan);
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        _pollTimer?.Dispose();
+        _justUpdatedResetTimer?.Dispose();
+        _cts.Cancel();
+        _cts.Dispose();
+        if (_hubConnection != null)
+        {
+            await _hubConnection.DisposeAsync();
+            _hubConnection = null;
+        }
+        if (_logsJs != null)
+        {
+            try { await _logsJs.DisposeAsync(); }
+            catch (InvalidOperationException ex) { Logger.LogDebug(ex, "AppLogsSection: DisposeAsync skipped (prerender)"); }
+            catch (JSDisconnectedException ex) { Logger.LogDebug(ex, "AppLogsSection: DisposeAsync skipped (circuit disconnected)"); }
+            catch (JSException ex) { Logger.LogDebug(ex, "AppLogsSection: DisposeAsync failed"); }
+            _logsJs = null;
+        }
+    }
+}

src/DnsmasqWebUI/Components/Dnsmasq/AppLogsSection.razor.css

@@ -0,0 +1,13 @@
+/* Status dot pulse – shared with StatusSection, LogsSection */
+@keyframes status-dot-pulse {
+    0%, 100% {
+        opacity: 1;
+    }
+    50% {
+        opacity: 0.35;
+    }
+}
+
+.status-dot.status-dot-updating {
+    animation: status-dot-pulse 0.7s ease-in-out infinite;
+}

src/DnsmasqWebUI/Components/Dnsmasq/LogsSection.razor

@@ -1,9 +1,19 @@
 @namespace DnsmasqWebUI.Components.Dnsmasq
-@* Recent logs — live view from LogsCommand; only this component re-renders on its timer *@
+@* Recent logs — live view via SignalR from LogsCommand; client polls at interval, server pushes deltas *@
+@using DnsmasqWebUI.Models.Logs
+@using Microsoft.AspNetCore.SignalR.Client
+@inject NavigationManager Navigation
+@inject IJSRuntime JSRuntime
+@inject ILogger<LogsSection> Logger
+@implements IAsyncDisposable
+
 @if (_status != null && (_status.LogsConfigured || _status.LogsPath != null))
 {
-    <p class="mb-1 mt-3 d-flex align-items-center justify-content-between">
+    <p class="mb-1 mt-3 d-flex align-items-center justify-content-between flex-wrap gap-1">
+        <span class="d-flex align-items-center gap-1">
             <strong>Recent logs</strong>
+            <span class="status-dot d-inline-block rounded-circle flex-shrink-0 bg-success @(_justUpdated ? "status-dot-updating" : null)" style="width: 0.5rem; height: 0.5rem;" title="@(_justUpdated ? "Updating…" : "Live")" aria-hidden="true"></span>
+        </span>
         <button type="button" class="btn btn-link btn-sm p-0 text-body" aria-label="Recent logs polling settings" @onclick="() => OnOpenSettings.InvokeAsync()" title="Configure recent logs polling interval">
             <i class="bi bi-gear-fill bi-gear-sm" aria-hidden="true"></i>
         </button>
@@ -14,17 +24,10 @@
     }
     @if (_status.LogsConfigured)
     {
-        @if (string.IsNullOrWhiteSpace(_status.LogsOutput))
-        {
-            <p class="text-muted small">No output.</p>
-        }
-        else
-        {
-            <pre class="pre-block mb-0" style="max-height: 24rem;">@_status.LogsOutput</pre>
-        }
+        <pre id="dnsmasq-logs-pre" class="pre-block mb-0" style="max-height: 24rem;">@_initialPlaceholder</pre>
     }
     <div class="mt-2 d-flex flex-wrap gap-2 align-items-center">
-        <button class="btn btn-primary btn-sm" @onclick="RefreshAsync" disabled="@_refreshing">Refresh</button>
+        <button class="btn btn-primary btn-sm" @onclick="RequestRefreshAsync" disabled="@_refreshing">Refresh</button>
         @if (_status.LogsPath != null)
         {
             <a href="api/status/logs/download" download="dnsmasq.log" class="btn btn-primary btn-sm">Download logs</a>

src/DnsmasqWebUI/Components/Dnsmasq/LogsSection.razor.cs

@@ -1,81 +1,181 @@
-using DnsmasqWebUI.Infrastructure.Client.Abstractions;
+using DnsmasqWebUI.Models.Client;
 using DnsmasqWebUI.Models.Dnsmasq;
+using DnsmasqWebUI.Models.Logs;
 using Microsoft.AspNetCore.Components;
+using Microsoft.AspNetCore.SignalR.Client;
+using Microsoft.JSInterop;
 
 namespace DnsmasqWebUI.Components.Dnsmasq;
 
 /// <summary>
-/// Recent logs block: polls LogsCommand output at its own interval and re-renders only itself.
+/// Recent logs block: connects to LogsHub, polls at interval via RequestDnsmasqLogs,
+/// receives DnsmasqLogsUpdate pushes, updates DOM via JS interop.
 /// </summary>
-public partial class LogsSection : IDisposable
+public partial class LogsSection : IAsyncDisposable
 {
+    private const string LogsPreId = "dnsmasq-logs-pre";
+
     private DnsmasqServiceStatus? _status;
     private bool _refreshing;
+    private bool _justUpdated;
     private int _intervalSeconds;
+    private HubConnection? _hubConnection;
+    private IJSObjectReference? _logsJs;
+    private Timer? _pollTimer;
+    private Timer? _justUpdatedResetTimer;
     private readonly CancellationTokenSource _cts = new();
-    private Timer? _timer;
+
+    [Parameter] public DnsmasqServiceStatus? Status { get; set; }
 
     [Parameter] public int RefreshIntervalSeconds { get; set; } = 15;
 
+    [Parameter] public int LogsMaxLines { get; set; } = 500;
+
+    [Parameter] public bool LogsAutoScroll { get; set; } = true;
+
     [Parameter] public EventCallback OnOpenSettings { get; set; }
 
-    [Inject] private IStatusClient StatusClient { get; set; } = null!;
+    private object LogsOptions => new { maxLines = LogsMaxLines, autoScroll = LogsAutoScroll };
 
-    protected override async Task OnInitializedAsync()
-    {
-        _intervalSeconds = Math.Clamp(RefreshIntervalSeconds, 5, 300);
-        await RefreshAsync();
-        _timer = new Timer(
-            _ => _ = InvokeAsync(OnRefreshTick),
-            null,
-            TimeSpan.FromSeconds(_intervalSeconds),
-            TimeSpan.FromSeconds(_intervalSeconds));
-    }
+    private string _initialPlaceholder => _hubConnection?.State == HubConnectionState.Connected ? "Waiting for logs…" : "Connecting…";
 
     protected override void OnParametersSet()
     {
-        var next = Math.Clamp(RefreshIntervalSeconds, 5, 300);
+        _status = Status;
+        var next = ClientSettingsFields.RecentLogsPollingInterval.Clamp(RefreshIntervalSeconds);
         if (next == _intervalSeconds) return;
         _intervalSeconds = next;
-        _timer?.Dispose();
-        _timer = new Timer(
-            _ => _ = InvokeAsync(OnRefreshTick),
+        RestartPollTimer();
+    }
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (!firstRender) return;
+        _intervalSeconds = ClientSettingsFields.RecentLogsPollingInterval.Clamp(RefreshIntervalSeconds);
+        _status = Status;
+
+        var hubUri = new Uri(new Uri(Navigation.BaseUri), "hubs/logs").ToString();
+
+        _hubConnection = new HubConnectionBuilder()
+            .WithUrl(hubUri)
+            .WithAutomaticReconnect()
+            .Build();
+
+        _hubConnection.On<LogsUpdatePayload>("DnsmasqLogsUpdate", OnDnsmasqLogsUpdate);
+
+        try
+        {
+            _logsJs = await JSRuntime.InvokeAsync<IJSObjectReference>("import", "./js/logs.js");
+        }
+        catch (InvalidOperationException ex) { Logger.LogDebug(ex, "LogsSection: JS import skipped (prerender)"); return; }
+        catch (JSDisconnectedException ex) { Logger.LogDebug(ex, "LogsSection: JS import skipped (circuit disconnected)"); return; }
+        catch (JSException ex) { Logger.LogDebug(ex, "LogsSection: JS import failed"); return; }
+
+        await _hubConnection.StartAsync(_cts.Token);
+        RestartPollTimer();
+
+        // Initial request
+        await RequestRefreshAsync();
+    }
+
+    private void RestartPollTimer()
+    {
+        _pollTimer?.Dispose();
+        _pollTimer = new Timer(
+            _ => _ = InvokeAsync(PollTick),
             null,
             TimeSpan.FromSeconds(_intervalSeconds),
             TimeSpan.FromSeconds(_intervalSeconds));
     }
 
-    private async Task OnRefreshTick()
+    private async Task PollTick()
     {
-        if (_cts.Token.IsCancellationRequested) return;
-        await RefreshAsync();
-        StateHasChanged();
+        if (_cts.Token.IsCancellationRequested || _hubConnection?.State != HubConnectionState.Connected)
+            return;
+        await RequestRefreshAsync();
     }
 
-    private async Task RefreshAsync()
+    private async Task RequestRefreshAsync()
     {
+        if (_hubConnection?.State != HubConnectionState.Connected)
+            return;
         _refreshing = true;
+        StateHasChanged();
         try
         {
-            var token = _cts.Token;
-            _status = await StatusClient.GetStatusAsync(token);
+            await _hubConnection.InvokeAsync("RequestDnsmasqLogs", _cts.Token);
         }
         catch (OperationCanceledException) { }
-        catch
+        catch (Exception)
         {
             // Don't overwrite on background refresh
         }
         finally
         {
             _refreshing = false;
+            StateHasChanged();
         }
     }
 
-    public void Dispose()
+    private async void OnDnsmasqLogsUpdate(LogsUpdatePayload payload)
     {
-        _timer?.Dispose();
-        _timer = null;
+        try
+        {
+            await InvokeAsync(async () =>
+            {
+                if (_logsJs == null) return;
+                try
+                {
+                    if (payload.Mode == "replace")
+                        await _logsJs.InvokeVoidAsync("replaceLogs", LogsPreId, payload.Content, LogsOptions);
+                    else
+                        await _logsJs.InvokeVoidAsync("appendLogs", LogsPreId, payload.Content, LogsOptions);
+                    SetJustUpdated();
+                    StateHasChanged();
+                }
+                catch (JSDisconnectedException) { /* Circuit disconnected; ignore */ }
+                catch (InvalidOperationException) { /* Prerender or circuit disposed; ignore */ }
+                catch (JSException) { /* JS error; ignore */ }
+            });
+        }
+        catch (ObjectDisposedException) { /* Component disposed; ignore */ }
+        catch (InvalidOperationException) { /* Circuit disconnected; ignore */ }
+    }
+
+    private void SetJustUpdated()
+    {
+        _justUpdated = true;
+        _justUpdatedResetTimer?.Dispose();
+        _justUpdatedResetTimer = new Timer(_ =>
+        {
+            _justUpdatedResetTimer?.Dispose();
+            _justUpdatedResetTimer = null;
+            _ = InvokeAsync(() =>
+            {
+                _justUpdated = false;
+                StateHasChanged();
+            });
+        }, null, TimeSpan.FromSeconds(2), Timeout.InfiniteTimeSpan);
+    }
+
+    public async ValueTask DisposeAsync()
+    {
+        _pollTimer?.Dispose();
+        _justUpdatedResetTimer?.Dispose();
         _cts.Cancel();
         _cts.Dispose();
+        if (_hubConnection != null)
+        {
+            await _hubConnection.DisposeAsync();
+            _hubConnection = null;
+        }
+        if (_logsJs != null)
+        {
+            try { await _logsJs.DisposeAsync(); }
+            catch (InvalidOperationException ex) { Logger.LogDebug(ex, "LogsSection: DisposeAsync skipped (prerender)"); }
+            catch (JSDisconnectedException ex) { Logger.LogDebug(ex, "LogsSection: DisposeAsync skipped (circuit disconnected)"); }
+            catch (JSException ex) { Logger.LogDebug(ex, "LogsSection: DisposeAsync failed"); }
+            _logsJs = null;
+        }
     }
 }

src/DnsmasqWebUI/Components/Dnsmasq/LogsSection.razor.css

@@ -0,0 +1,13 @@
+/* Status dot pulse – shared with StatusSection */
+@keyframes status-dot-pulse {
+    0%, 100% {
+        opacity: 1;
+    }
+    50% {
+        opacity: 0.35;
+    }
+}
+
+.status-dot.status-dot-updating {
+    animation: status-dot-pulse 0.7s ease-in-out infinite;
+}

src/DnsmasqWebUI/Components/Dnsmasq/StatusSection.razor.cs

@@ -1,4 +1,5 @@
 using DnsmasqWebUI.Infrastructure.Client.Abstractions;
+using DnsmasqWebUI.Models.Client;
 using DnsmasqWebUI.Models.Dnsmasq;
 using Microsoft.AspNetCore.Components;
 
@@ -25,7 +26,7 @@ public partial class StatusSection : IDisposable
 
     protected override async Task OnInitializedAsync()
     {
-        _intervalSeconds = Math.Clamp(RefreshIntervalSeconds, 5, 300);
+        _intervalSeconds = ClientSettingsFields.ServiceStatusPollingInterval.Clamp(RefreshIntervalSeconds);
         await RefreshAsync();
         _timer = new Timer(
             _ => _ = InvokeAsync(OnRefreshTick),
@@ -36,7 +37,7 @@ public partial class StatusSection : IDisposable
 
     protected override void OnParametersSet()
     {
-        var next = Math.Clamp(RefreshIntervalSeconds, 5, 300);
+        var next = ClientSettingsFields.ServiceStatusPollingInterval.Clamp(RefreshIntervalSeconds);
         if (next == _intervalSeconds) return;
         _intervalSeconds = next;
         _timer?.Dispose();

src/DnsmasqWebUI/Components/Layout/NavMenu.razor

@@ -3,16 +3,18 @@
 @inject ISettingsModalService SettingsModalService
 
 <div class="top-row ps-3 navbar navbar-dark">
-    <div class="container-fluid d-flex align-items-center">
+    <div class="top-row-inner">
         <a class="navbar-brand d-flex align-items-center gap-2" href="" aria-label="@AppTitle home">
             <span class="brand-logo-wrap"><img src="logo.webp" alt="" class="brand-logo" /></span>
             <span>@AppTitle</span>
         </a>
+        <div class="nav-top-controls">
             <button type="button" class="nav-settings-btn" aria-label="Settings" title="Settings" @onclick="OpenAllSettings">
                 <i class="bi bi-gear-fill" aria-hidden="true"></i>
             </button>
-    </div>
             <input type="checkbox" title="Navigation menu" class="navbar-toggler" id="nav-toggler" aria-label="Toggle navigation" />
+        </div>
+    </div>
 </div>
 
 <div class="nav-scrollable" onclick="document.getElementById('nav-toggler')?.click()">

src/DnsmasqWebUI/Components/Layout/NavMenu.razor.css

@@ -1,13 +1,34 @@
+.top-row {
+    min-height: 3.5rem;
+    background-color: rgba(0,0,0,0.4);
+}
+
+/* Flex row: brand left, controls right; single line, aligned with brand. */
+.top-row-inner {
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    width: 100%;
+    padding: 0.5rem 1rem 0.5rem 0.75rem;
+    box-sizing: border-box;
+}
+
+/* Settings + hamburger: push right, align with brand */
+.nav-top-controls {
+    margin-left: auto;
+    display: flex;
+    align-items: center;
+    gap: 0.5rem;
+    flex-shrink: 0;
+}
+
 .navbar-toggler {
     appearance: none;
     cursor: pointer;
+    flex-shrink: 0;
     width: 3.5rem;
     height: 2.5rem;
     color: white;
-    position: absolute;
-    top: 50%;
-    right: 1rem;
-    transform: translateY(-50%);
     border: 1px solid rgba(255, 255, 255, 0.1);
     background: url("data:image/svg+xml,%3csvg xmlns='http://www.w3.org/2000/svg' viewBox='0 0 30 30'%3e%3cpath stroke='rgba%28255, 255, 255, 0.55%29' stroke-linecap='round' stroke-miterlimit='10' stroke-width='2' d='M4 7h22M4 15h22M4 23h22'/%3e%3c/svg%3e") no-repeat center/1.75rem rgba(255, 255, 255, 0.1);
 }
@@ -16,17 +37,11 @@
     background-color: rgba(255, 255, 255, 0.5);
 }
 
-.top-row {
-    position: relative;
-    min-height: 3.5rem;
-    background-color: rgba(0,0,0,0.4);
-}
-
-/* Settings button: right of brand, same visual style as nav. On mobile, leaves space for toggler. */
+/* Settings button: same height as toggler on mobile for alignment */
 .nav-settings-btn {
-    margin-left: auto;
-    margin-right: 0.5rem;
     padding: 0.375rem 0.5rem;
+    height: 2.5rem;
+    box-sizing: border-box;
     background: transparent;
     border: 1px solid rgba(255, 255, 255, 0.15);
     border-radius: 0.375rem;
@@ -47,25 +62,29 @@
     font-size: 1.25rem;
 }
 
-/* On mobile: leave space for toggler (right: 1rem, width 3.5rem) so settings doesn't overlap */
-@media (max-width: 640.98px) {
-    .nav-settings-btn {
-        margin-right: 4rem;
-    }
-}
-
 .navbar-brand {
     font-size: 1.1rem;
     font-weight: 600;
     text-decoration: none;
     color: rgba(255, 255, 255, 0.95) !important;
+    flex-shrink: 0;
 }
 
 .navbar-brand:hover {
     color: white !important;
 }
 
-/* Logo size/alignment: see app.css .sidebar .navbar-brand .brand-logo-wrap / .brand-logo */
+/* Smaller logo on mobile so controls align with brand text */
+@media (max-width: 640.98px) {
+    .top-row .navbar-brand .brand-logo-wrap {
+        width: 2.5rem;
+        height: 2.5rem;
+    }
+
+    .top-row .navbar-brand .brand-logo {
+        height: 2.5rem;
+    }
+}
 
 /* Bootstrap Icons in nav: white, sized to match link text */
 .nav-item .nav-icon {
@@ -116,7 +135,8 @@
     display: none;
 }
 
-.navbar-toggler:checked ~ .nav-scrollable {
+/* Toggler is inside top-row; nav-scrollable is sibling of top-row */
+.top-row:has(.navbar-toggler:checked) ~ .nav-scrollable {
     display: block;
 }
 

src/DnsmasqWebUI/Components/Modals/SettingsModal.razor

@@ -2,6 +2,7 @@
 @implements IAsyncDisposable
 @inject IJSRuntime JSRuntime
 @inject IClientSettingsService ClientSettingsService
+@inject ILogger<SettingsModal> Logger
 
 @if (IsVisible)
 {
@@ -12,6 +13,18 @@
                 <button type="button" class="btn-close" @onclick="Close" aria-label="Close"></button>
             </div>
             <div class="modal-body">
+                @if (_validationErrors.Count > 0)
+                {
+                    <div class="alert alert-danger mb-3" role="alert">
+                        <strong>Please fix the following:</strong>
+                        <ul class="mb-0 mt-1">
+                            @foreach (var err in _validationErrors)
+                            {
+                                <li>@err</li>
+                            }
+                        </ul>
+                    </div>
+                }
                 @if (SettingsContext == SettingsModalContext.All)
                 {
                     <div class="mb-3">
@@ -26,7 +39,7 @@
                     <section class="mb-4">
                         <h6 class="text-muted">@meta.DisplayName</h6>
                         <label for="status-interval" class="form-label">@meta.FieldLabel</label>
-                        <input id="status-interval" type="number" class="form-control" min="5" step="1"
+                        <input id="status-interval" type="number" class="form-control" min="@ClientSettingsFields.ServiceStatusPollingInterval.Min" max="@ClientSettingsFields.ServiceStatusPollingInterval.Max" step="1"
                                @bind="_editingSettings.ServiceStatusPollingIntervalSeconds" />
                     </section>
                 }
@@ -36,20 +49,62 @@
                     <section class="mb-4">
                         <h6 class="text-muted">@meta.DisplayName</h6>
                         <label for="logs-interval" class="form-label">@meta.FieldLabel</label>
-                        <input id="logs-interval" type="number" class="form-control" min="5" step="1"
+                        <input id="logs-interval" type="number" class="form-control" min="@ClientSettingsFields.RecentLogsPollingInterval.Min" max="@ClientSettingsFields.RecentLogsPollingInterval.Max" step="1"
                                @bind="_editingSettings.RecentLogsPollingIntervalSeconds" />
                     </section>
                 }
+                @if (ShouldShowSection(SettingsModalSections.AppLogs))
+                {
+                    var meta = SettingsModalSections.All[SettingsModalSections.AppLogs];
+                    <section class="mb-4">
+                        <h6 class="text-muted">@meta.DisplayName</h6>
+                        <label for="app-logs-interval" class="form-label">@meta.FieldLabel</label>
+                        <input id="app-logs-interval" type="number" class="form-control" min="@ClientSettingsFields.AppLogsPollingInterval.Min" max="@ClientSettingsFields.AppLogsPollingInterval.Max" step="1"
+                               @bind="_editingSettings.AppLogsPollingIntervalSeconds" />
+                    </section>
+                }
                 @if (ShouldShowSection(SettingsModalSections.Leases))
                 {
                     var meta = SettingsModalSections.All[SettingsModalSections.Leases];
                     <section class="mb-4">
                         <h6 class="text-muted">@meta.DisplayName</h6>
                         <label for="leases-interval" class="form-label">@meta.FieldLabel</label>
-                        <input id="leases-interval" type="number" class="form-control" min="5" step="1"
+                        <input id="leases-interval" type="number" class="form-control" min="@ClientSettingsFields.LeasesPollingInterval.Min" max="@ClientSettingsFields.LeasesPollingInterval.Max" step="1"
                                @bind="_editingSettings.LeasesPollingIntervalSeconds" />
                     </section>
                 }
+                @if (ShouldShowSection(SettingsModalSections.RecentLogsDisplay))
+                {
+                    var meta = SettingsModalSections.All[SettingsModalSections.RecentLogsDisplay];
+                    <section class="mb-4">
+                        <h6 class="text-muted">@meta.DisplayName</h6>
+                        <div class="mb-2">
+                            <label for="recent-logs-max-lines" class="form-label">Max lines</label>
+                            <input id="recent-logs-max-lines" type="number" class="form-control" min="@ClientSettingsFields.RecentLogsMaxLines.Min" max="@ClientSettingsFields.RecentLogsMaxLines.Max" step="1"
+                                   @bind="_editingSettings.RecentLogsMaxLines" />
+                        </div>
+                        <div class="form-check">
+                            <input id="recent-logs-auto-scroll" type="checkbox" class="form-check-input" @bind="_editingSettings.RecentLogsAutoScroll" />
+                            <label for="recent-logs-auto-scroll" class="form-check-label">Auto-scroll when new logs arrive</label>
+                        </div>
+                    </section>
+                }
+                @if (ShouldShowSection(SettingsModalSections.AppLogsDisplay))
+                {
+                    var meta = SettingsModalSections.All[SettingsModalSections.AppLogsDisplay];
+                    <section class="mb-4">
+                        <h6 class="text-muted">@meta.DisplayName</h6>
+                        <div class="mb-2">
+                            <label for="app-logs-max-lines" class="form-label">Max lines</label>
+                            <input id="app-logs-max-lines" type="number" class="form-control" min="@ClientSettingsFields.AppLogsMaxLines.Min" max="@ClientSettingsFields.AppLogsMaxLines.Max" step="1"
+                                   @bind="_editingSettings.AppLogsMaxLines" />
+                        </div>
+                        <div class="form-check">
+                            <input id="app-logs-auto-scroll" type="checkbox" class="form-check-input" @bind="_editingSettings.AppLogsAutoScroll" />
+                            <label for="app-logs-auto-scroll" class="form-check-label">Auto-scroll when new logs arrive</label>
+                        </div>
+                    </section>
+                }
             </div>
             <div class="modal-footer">
                 <button type="button" class="btn btn-secondary" @onclick="Close">Cancel</button>

src/DnsmasqWebUI/Components/Modals/SettingsModal.razor.cs

@@ -16,6 +16,7 @@ public partial class SettingsModal : IAsyncDisposable
     private IJSObjectReference? _jsModule;
     private DotNetObjectReference<SettingsModal>? _dotNetRef;
     private ClientSettings _editingSettings = new();
+    private List<string> _validationErrors = new();
     private string _searchTerm = string.Empty;
     private bool _moduleLoaded;
     private bool _dialogInitialized;
@@ -39,12 +40,18 @@ public partial class SettingsModal : IAsyncDisposable
         if (justOpened)
         {
             _searchTerm = string.Empty;
+            _validationErrors.Clear();
             _editingSettings = await ClientSettingsService.LoadSettingsAsync();
             _editingSettings = new ClientSettings
             {
                 ServiceStatusPollingIntervalSeconds = _editingSettings.ServiceStatusPollingIntervalSeconds,
                 RecentLogsPollingIntervalSeconds = _editingSettings.RecentLogsPollingIntervalSeconds,
-                LeasesPollingIntervalSeconds = _editingSettings.LeasesPollingIntervalSeconds
+                AppLogsPollingIntervalSeconds = _editingSettings.AppLogsPollingIntervalSeconds,
+                LeasesPollingIntervalSeconds = _editingSettings.LeasesPollingIntervalSeconds,
+                RecentLogsMaxLines = _editingSettings.RecentLogsMaxLines,
+                RecentLogsAutoScroll = _editingSettings.RecentLogsAutoScroll,
+                AppLogsMaxLines = _editingSettings.AppLogsMaxLines,
+                AppLogsAutoScroll = _editingSettings.AppLogsAutoScroll
             };
         }
     }
@@ -52,11 +59,17 @@ public partial class SettingsModal : IAsyncDisposable
     protected override async Task OnAfterRenderAsync(bool firstRender)
     {
         if (firstRender)
+        {
+            try
             {
                 _jsModule = await JSRuntime.InvokeAsync<IJSObjectReference>("import", "./js/settings-modal.js");
                 _dotNetRef = DotNetObjectReference.Create(this);
                 _moduleLoaded = true;
             }
+            catch (InvalidOperationException ex) { Logger.LogDebug(ex, "SettingsModal: JS import skipped (prerender)"); }
+            catch (JSDisconnectedException ex) { Logger.LogDebug(ex, "SettingsModal: JS import skipped (circuit disconnected)"); }
+            catch (JSException ex) { Logger.LogDebug(ex, "SettingsModal: JS import failed"); }
+        }
 
         if (IsVisible && _moduleLoaded && _jsModule != null)
         {
@@ -73,31 +86,48 @@ public partial class SettingsModal : IAsyncDisposable
 
     private bool ShouldShowSection(string key)
     {
-        var focusedKey = SettingsModalSections.GetSectionKeyForContext(SettingsContext);
-        if (focusedKey != null)
-            return string.Equals(key, focusedKey, StringComparison.OrdinalIgnoreCase);
+        var keys = SettingsModalSections.GetSectionKeysForContext(SettingsContext);
+        if (keys != null)
+            return keys.Any(k => string.Equals(key, k, StringComparison.OrdinalIgnoreCase));
         return SettingsModalSections.MatchesSearch(key, _searchTerm);
     }
 
+    private void RunValidation()
+    {
+        _validationErrors.Clear();
+        var checks = new (string Section, int Value, ClientSettingsFields.FieldBounds Bounds)[]
+        {
+            (SettingsModalSections.ServiceStatus, _editingSettings.ServiceStatusPollingIntervalSeconds, ClientSettingsFields.ServiceStatusPollingInterval),
+            (SettingsModalSections.Logs, _editingSettings.RecentLogsPollingIntervalSeconds, ClientSettingsFields.RecentLogsPollingInterval),
+            (SettingsModalSections.AppLogs, _editingSettings.AppLogsPollingIntervalSeconds, ClientSettingsFields.AppLogsPollingInterval),
+            (SettingsModalSections.Leases, _editingSettings.LeasesPollingIntervalSeconds, ClientSettingsFields.LeasesPollingInterval),
+            (SettingsModalSections.RecentLogsDisplay, _editingSettings.RecentLogsMaxLines, ClientSettingsFields.RecentLogsMaxLines),
+            (SettingsModalSections.AppLogsDisplay, _editingSettings.AppLogsMaxLines, ClientSettingsFields.AppLogsMaxLines),
+        };
+        foreach (var (section, value, bounds) in checks)
+        {
+            if (ShouldShowSection(section) && bounds.Validate(value) is { } err)
+                _validationErrors.Add(err);
+        }
+    }
+
     private async Task Save()
     {
-        _editingSettings.ServiceStatusPollingIntervalSeconds = Math.Clamp(
-            _editingSettings.ServiceStatusPollingIntervalSeconds, 5, 300);
-        _editingSettings.RecentLogsPollingIntervalSeconds = Math.Clamp(
-            _editingSettings.RecentLogsPollingIntervalSeconds, 5, 300);
-        _editingSettings.LeasesPollingIntervalSeconds = Math.Clamp(
-            _editingSettings.LeasesPollingIntervalSeconds, 5, 300);
+        RunValidation();
+        if (_validationErrors.Count > 0)
+        {
+            await InvokeAsync(StateHasChanged);
+            return;
+        }
 
         await ClientSettingsService.SaveSettingsAsync(_editingSettings);
-        if (_jsModule != null)
-            await _jsModule.InvokeVoidAsync("closeModal", _dialogRef);
+        await (_jsModule?.InvokeVoidAsync("closeModal", _dialogRef) ?? ValueTask.CompletedTask);
         await OnClose.InvokeAsync();
     }
 
     private async Task Close()
     {
-        if (_jsModule != null)
-            await _jsModule.InvokeVoidAsync("closeModal", _dialogRef);
+        await (_jsModule?.InvokeVoidAsync("closeModal", _dialogRef) ?? ValueTask.CompletedTask);
         await OnClose.InvokeAsync();
     }
 
@@ -112,14 +142,13 @@ public partial class SettingsModal : IAsyncDisposable
     /// Disposes JS module and DotNetObjectReference. Blazor calls this when the component is removed from the tree.
     /// </summary>
     public async ValueTask DisposeAsync()
-    {
-        try
     {
         if (_jsModule != null)
-                await _jsModule.DisposeAsync();
-        }
-        finally
         {
+            try { await _jsModule.DisposeAsync(); }
+            catch (InvalidOperationException ex) { Logger.LogDebug(ex, "SettingsModal: DisposeAsync skipped (prerender)"); }
+            catch (JSDisconnectedException ex) { Logger.LogDebug(ex, "SettingsModal: DisposeAsync skipped (circuit disconnected)"); }
+            catch (JSException ex) { Logger.LogDebug(ex, "SettingsModal: DisposeAsync failed"); }
             _jsModule = null;
         }
         _dotNetRef?.Dispose();

src/DnsmasqWebUI/Components/Pages/Dhcp.razor

@@ -399,10 +399,16 @@ else
         ("2592000", "30 days"),
     };
 
-    protected override async Task OnInitializedAsync()
+    protected override void OnInitialized()
     {
         SettingsModalService.SettingsChanged += OnSettingsChanged;
+    }
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (!firstRender) return;
         await Load();
+        StateHasChanged();
     }
 
     private async Task Load()
@@ -412,7 +418,7 @@ else
         try
         {
             var clientSettings = await ClientSettingsService.LoadSettingsAsync();
-            _leasesRefreshIntervalSeconds = Math.Clamp(clientSettings.LeasesPollingIntervalSeconds, 5, 300);
+            _leasesRefreshIntervalSeconds = ClientSettingsFields.LeasesPollingInterval.Clamp(clientSettings.LeasesPollingIntervalSeconds);
             _status = await StatusClient.GetStatusAsync();
             var entries = await DhcpHostsClient.GetDhcpHostsAsync();
             _entries = entries?.ToList() ?? new List<DhcpHostEntry>();
@@ -433,7 +439,7 @@ else
         await InvokeAsync(async () =>
         {
             var clientSettings = await ClientSettingsService.LoadSettingsAsync();
-            _leasesRefreshIntervalSeconds = Math.Clamp(clientSettings.LeasesPollingIntervalSeconds, 5, 300);
+            _leasesRefreshIntervalSeconds = ClientSettingsFields.LeasesPollingInterval.Clamp(clientSettings.LeasesPollingIntervalSeconds);
             if (_status != null && _status.LeasesPathConfigured)
                 StartLeasesRefreshTimer();
             StateHasChanged();

src/DnsmasqWebUI/Components/Pages/Dnsmasq.razor

@@ -79,7 +79,8 @@ else if (_status != null)
         }
 
         <StatusSection RefreshIntervalSeconds="_serviceStatusIntervalSeconds" IsReloading="_reloading" OnOpenSettings="OpenServiceStatusSettings" />
-        <LogsSection RefreshIntervalSeconds="_recentLogsIntervalSeconds" OnOpenSettings="OpenRecentLogsSettings" />
+        <LogsSection Status="_status" RefreshIntervalSeconds="_recentLogsIntervalSeconds" LogsMaxLines="_recentLogsMaxLines" LogsAutoScroll="_recentLogsAutoScroll" OnOpenSettings="OpenRecentLogsSettings" />
+        <AppLogsSection RefreshIntervalSeconds="_appLogsIntervalSeconds" LogsMaxLines="_appLogsMaxLines" LogsAutoScroll="_appLogsAutoScroll" OnOpenSettings="OpenAppLogsSettings" />
     </section>
 }
 
@@ -87,6 +88,11 @@ else if (_status != null)
     private string AppTitle => AppOptions!.Value!.EffectiveTitle;
     private int _serviceStatusIntervalSeconds = 15;
     private int _recentLogsIntervalSeconds = 15;
+    private int _appLogsIntervalSeconds = 15;
+    private int _recentLogsMaxLines = 500;
+    private bool _recentLogsAutoScroll = true;
+    private int _appLogsMaxLines = 500;
+    private bool _appLogsAutoScroll = true;
 
     private DnsmasqServiceStatus? _status;
     private DnsmasqConfigSet? _configSet;
@@ -98,17 +104,27 @@ else if (_status != null)
     private bool _reloadSuccess;
     private readonly CancellationTokenSource _cts = new();
 
-    protected override async Task OnInitializedAsync()
+    protected override void OnInitialized()
     {
         SettingsModalService.SettingsChanged += OnSettingsChanged;
+    }
+
+    protected override async Task OnAfterRenderAsync(bool firstRender)
+    {
+        if (!firstRender) return;
         _loading = true;
         try
         {
             await Task.Delay(1, _cts.Token);
             var token = _cts.Token;
             var clientSettings = await ClientSettingsService.LoadSettingsAsync();
-            _serviceStatusIntervalSeconds = Math.Clamp(clientSettings.ServiceStatusPollingIntervalSeconds, 5, 300);
-            _recentLogsIntervalSeconds = Math.Clamp(clientSettings.RecentLogsPollingIntervalSeconds, 5, 300);
+            _serviceStatusIntervalSeconds = ClientSettingsFields.ServiceStatusPollingInterval.Clamp(clientSettings.ServiceStatusPollingIntervalSeconds);
+            _recentLogsIntervalSeconds = ClientSettingsFields.RecentLogsPollingInterval.Clamp(clientSettings.RecentLogsPollingIntervalSeconds);
+            _appLogsIntervalSeconds = ClientSettingsFields.AppLogsPollingInterval.Clamp(clientSettings.AppLogsPollingIntervalSeconds);
+            _recentLogsMaxLines = ClientSettingsFields.RecentLogsMaxLines.Clamp(clientSettings.RecentLogsMaxLines);
+            _recentLogsAutoScroll = clientSettings.RecentLogsAutoScroll;
+            _appLogsMaxLines = ClientSettingsFields.AppLogsMaxLines.Clamp(clientSettings.AppLogsMaxLines);
+            _appLogsAutoScroll = clientSettings.AppLogsAutoScroll;
             _status = await StatusClient.GetStatusAsync(token);
             if (_status != null)
             {
@@ -133,6 +149,7 @@ else if (_status != null)
         finally
         {
             _loading = false;
+            StateHasChanged();
         }
     }
 
@@ -140,13 +157,20 @@ else if (_status != null)
 
     private void OpenRecentLogsSettings() => SettingsModalService.Open(SettingsModalContext.LogsPolling, "Recent logs polling");
 
+    private void OpenAppLogsSettings() => SettingsModalService.Open(SettingsModalContext.AppLogsPolling, "App logs polling");
+
     private async void OnSettingsChanged()
     {
         await InvokeAsync(async () =>
         {
             var clientSettings = await ClientSettingsService.LoadSettingsAsync();
-            _serviceStatusIntervalSeconds = Math.Clamp(clientSettings.ServiceStatusPollingIntervalSeconds, 5, 300);
-            _recentLogsIntervalSeconds = Math.Clamp(clientSettings.RecentLogsPollingIntervalSeconds, 5, 300);
+            _serviceStatusIntervalSeconds = ClientSettingsFields.ServiceStatusPollingInterval.Clamp(clientSettings.ServiceStatusPollingIntervalSeconds);
+            _recentLogsIntervalSeconds = ClientSettingsFields.RecentLogsPollingInterval.Clamp(clientSettings.RecentLogsPollingIntervalSeconds);
+            _appLogsIntervalSeconds = ClientSettingsFields.AppLogsPollingInterval.Clamp(clientSettings.AppLogsPollingIntervalSeconds);
+            _recentLogsMaxLines = ClientSettingsFields.RecentLogsMaxLines.Clamp(clientSettings.RecentLogsMaxLines);
+            _recentLogsAutoScroll = clientSettings.RecentLogsAutoScroll;
+            _appLogsMaxLines = ClientSettingsFields.AppLogsMaxLines.Clamp(clientSettings.AppLogsMaxLines);
+            _appLogsAutoScroll = clientSettings.AppLogsAutoScroll;
             StateHasChanged();
         });
     }

src/DnsmasqWebUI/Controllers/ConfigController.cs

@@ -1,9 +1,11 @@
+using DnsmasqWebUI.Infrastructure.Logging;
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
 using DnsmasqWebUI.Models.Config;
+using DnsmasqWebUI.Models.Contracts;
 using DnsmasqWebUI.Models.Dnsmasq;
 using DnsmasqWebUI.Models.Dnsmasq.EffectiveConfig;
-using DnsmasqWebUI.Models.Contracts;
-using DnsmasqWebUI.Infrastructure.Services.Abstractions;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
 
 namespace DnsmasqWebUI.Controllers;
 
@@ -14,12 +16,14 @@ public class ConfigController : ControllerBase
     private readonly IDnsmasqConfigSetService _configSetService;
     private readonly IDnsmasqConfigService _configService;
     private readonly IReloadService _reloadService;
+    private readonly ILogger<ConfigController> _logger;
 
-    public ConfigController(IDnsmasqConfigSetService configSetService, IDnsmasqConfigService configService, IReloadService reloadService)
+    public ConfigController(IDnsmasqConfigSetService configSetService, IDnsmasqConfigService configService, IReloadService reloadService, ILogger<ConfigController> logger)
     {
         _configSetService = configSetService;
         _configService = configService;
         _reloadService = reloadService;
+        _logger = logger;
     }
 
     /// <summary>Returns the config set (main + conf-file/conf-dir) and managed file path. Read-only structure for UI.</summary>
@@ -28,11 +32,13 @@ public class ConfigController : ControllerBase
     {
         try
         {
+            _logger.LogDebug("Get config set");
             var set = await _configSetService.GetConfigSetAsync(ct);
             return Ok(set);
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.ConfigGetSetFailed, ex, "Get config set failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }
@@ -43,11 +49,13 @@ public class ConfigController : ControllerBase
     {
         try
         {
+            _logger.LogDebug("Get managed config");
             var content = await _configService.ReadManagedConfigAsync(ct);
             return Ok(content);
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.ConfigGetManagedFailed, ex, "Get managed config failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }
@@ -62,10 +70,12 @@ public class ConfigController : ControllerBase
         {
             await _configService.WriteManagedConfigAsync(lines, ct);
             var reload = await _reloadService.ReloadAsync(ct);
+            _logger.LogInformation(LogEvents.ConfigPutManagedSuccess, "Config managed updated, reload success={Success}", reload.Success);
             return Ok(new { saved = true, reload = new { reload.Success, reload.ExitCode, reload.StdErr } });
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.ConfigPutManagedFailed, ex, "Put managed config failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }

src/DnsmasqWebUI/Controllers/DhcpController.cs

@@ -1,7 +1,9 @@
+using DnsmasqWebUI.Infrastructure.Logging;
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
 using DnsmasqWebUI.Models.Dhcp;
 using DnsmasqWebUI.Models.Dnsmasq;
-using DnsmasqWebUI.Infrastructure.Services.Abstractions;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
 
 namespace DnsmasqWebUI.Controllers;
 
@@ -11,11 +13,13 @@ public class DhcpController : ControllerBase
 {
     private readonly IDnsmasqConfigService _configService;
     private readonly IReloadService _reloadService;
+    private readonly ILogger<DhcpController> _logger;
 
-    public DhcpController(IDnsmasqConfigService configService, IReloadService reloadService)
+    public DhcpController(IDnsmasqConfigService configService, IReloadService reloadService, ILogger<DhcpController> logger)
     {
         _configService = configService;
         _reloadService = reloadService;
+        _logger = logger;
     }
 
     [HttpGet("hosts")]
@@ -23,11 +27,13 @@ public class DhcpController : ControllerBase
     {
         try
         {
+            _logger.LogDebug("Get DHCP hosts");
             var entries = await _configService.ReadDhcpHostsAsync(ct);
             return Ok(entries);
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.DhcpGetHostsFailed, ex, "Get DHCP hosts failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }
@@ -41,14 +47,17 @@ public class DhcpController : ControllerBase
         {
             await _configService.WriteDhcpHostsAsync(entries, ct);
             var reload = await _reloadService.ReloadAsync(ct);
+            _logger.LogInformation(LogEvents.DhcpPutHostsSuccess, "DHCP hosts saved, count={Count}, reload success={Success}", entries.Count, reload.Success);
             return Ok(new SaveWithReloadResult(true, reload));
         }
         catch (ArgumentException ex)
         {
+            _logger.LogWarning(LogEvents.DhcpPutHostsValidationFailed, ex, "DHCP hosts put validation failed");
             return BadRequest(new { error = ex.Message });
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.DhcpPutHostsFailed, ex, "Put DHCP hosts failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }

src/DnsmasqWebUI/Controllers/HostsController.cs

@@ -1,7 +1,9 @@
-using DnsmasqWebUI.Models.Hosts;
-using DnsmasqWebUI.Models.Dnsmasq;
+using DnsmasqWebUI.Infrastructure.Logging;
 using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using DnsmasqWebUI.Models.Dnsmasq;
+using DnsmasqWebUI.Models.Hosts;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
 
 namespace DnsmasqWebUI.Controllers;
 
@@ -12,12 +14,14 @@ public class HostsController : ControllerBase
     private readonly IHostsFileService _hostsService;
     private readonly IReloadService _reloadService;
     private readonly IHostsCache _hostsCache;
+    private readonly ILogger<HostsController> _logger;
 
-    public HostsController(IHostsFileService hostsService, IReloadService reloadService, IHostsCache hostsCache)
+    public HostsController(IHostsFileService hostsService, IReloadService reloadService, IHostsCache hostsCache, ILogger<HostsController> logger)
     {
         _hostsService = hostsService;
         _reloadService = reloadService;
         _hostsCache = hostsCache;
+        _logger = logger;
     }
 
     [HttpGet]
@@ -25,11 +29,13 @@ public class HostsController : ControllerBase
     {
         try
         {
+            _logger.LogDebug("Get hosts");
             var entries = await _hostsService.ReadAsync(ct);
             return Ok(entries);
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.HostsGetFailed, ex, "Get hosts failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }
@@ -40,11 +46,13 @@ public class HostsController : ControllerBase
     {
         try
         {
+            _logger.LogDebug("Get readonly hosts");
             var snapshot = await _hostsCache.GetSnapshotAsync(ct);
             return Ok(snapshot.ReadOnlyFiles);
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.HostsGetReadOnlyFailed, ex, "Get readonly hosts failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }
@@ -58,14 +66,17 @@ public class HostsController : ControllerBase
         {
             await _hostsService.WriteAsync(entries, ct);
             var reload = await _reloadService.ReloadAsync(ct);
+            _logger.LogInformation(LogEvents.HostsPutSuccess, "Hosts saved, count={Count}, reload success={Success}", entries.Count, reload.Success);
             return Ok(new SaveWithReloadResult(true, reload));
         }
         catch (InvalidOperationException ex)
         {
+            _logger.LogWarning(LogEvents.HostsPutValidationFailed, ex, "Hosts put validation failed");
             return BadRequest(new { error = ex.Message });
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.HostsPutFailed, ex, "Put hosts failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }

src/DnsmasqWebUI/Controllers/LeasesController.cs

@@ -1,6 +1,8 @@
-using DnsmasqWebUI.Models.Dhcp;
+using DnsmasqWebUI.Infrastructure.Logging;
 using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using DnsmasqWebUI.Models.Dhcp;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
 
 namespace DnsmasqWebUI.Controllers;
 
@@ -10,11 +12,13 @@ public class LeasesController : ControllerBase
 {
     private readonly ILeasesFileService _leasesService;
     private readonly ILeasesCache _cache;
+    private readonly ILogger<LeasesController> _logger;
 
-    public LeasesController(ILeasesFileService leasesService, ILeasesCache cache)
+    public LeasesController(ILeasesFileService leasesService, ILeasesCache cache, ILogger<LeasesController> logger)
     {
         _leasesService = leasesService;
         _cache = cache;
+        _logger = logger;
     }
 
     [HttpGet]
@@ -22,6 +26,7 @@ public class LeasesController : ControllerBase
     {
         try
         {
+            _logger.LogDebug("Get leases, refresh={Refresh}", refresh);
             if (refresh)
                 _cache.Invalidate();
             var (available, entries) = await _leasesService.TryReadAsync(ct);
@@ -33,6 +38,7 @@ public class LeasesController : ControllerBase
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.LeasesGetFailed, ex, "Get leases failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }

src/DnsmasqWebUI/Controllers/LoggingController.cs

@@ -0,0 +1,221 @@
+using System.Text.Json;
+using System.Text.Json.Nodes;
+using DnsmasqWebUI.Infrastructure.Logging;
+using DnsmasqWebUI.Models.Config;
+using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Options;
+
+namespace DnsmasqWebUI.Controllers;
+
+[ApiController]
+[Route("api/[controller]")]
+public class LoggingController : ControllerBase
+{
+    private readonly IConfiguration _configuration;
+    private readonly IConfigurationRoot _configurationRoot;
+    private readonly RuntimeOverridesOptions _overridesOptions;
+    private readonly ILogger<LoggingController> _logger;
+
+    public LoggingController(
+        IConfiguration configuration,
+        IOptions<RuntimeOverridesOptions> overridesOptions,
+        ILogger<LoggingController> logger)
+    {
+        _configuration = configuration;
+        _configurationRoot = (IConfigurationRoot)configuration;
+        _overridesOptions = overridesOptions.Value;
+        _logger = logger;
+    }
+
+    /// <summary>Get the current minimum log level from configuration (Logging:LogLevel:Default).</summary>
+    [HttpGet("level")]
+    public ActionResult<LogLevelResponse> GetLevel()
+    {
+        var level = ParseLevel(_configuration["Logging:LogLevel:Default"]) ?? LogLevel.Information;
+        return Ok(new LogLevelResponse(LevelName(level)));
+    }
+
+    /// <summary>Set the minimum log level. Writes to appsettings.Overrides.json and reloads config.</summary>
+    [HttpPost("level")]
+    public ActionResult<LogLevelResponse> SetLevel([FromBody] LogLevelRequest request)
+    {
+        var level = ParseLevel(request?.LogLevel);
+        if (level == null)
+        {
+            _logger.LogWarning(LogEvents.LogLevelSetBadRequest, "Set log level failed: invalid level requested");
+            return BadRequest(new { error = "Invalid LogLevel. Use Trace, Debug, Information, Warning, Error, or Critical." });
+        }
+
+        var path = GetOverridesPath();
+        if (!TryUpdateOverrides(path, logLevel: level.Value, excludedPrefixes: null))
+        {
+            _logger.LogError(LogEvents.LogLevelSetFailed, "Failed to write log level overrides file to {Path}", path);
+            return StatusCode(500, new { error = "Failed to write overrides file." });
+        }
+
+        _configurationRoot.Reload();
+        _logger.LogInformation(LogEvents.LogLevelChanged, "Log level changed to {Level}", LevelName(level.Value));
+        return Ok(new LogLevelResponse(LevelName(level.Value)));
+    }
+
+    /// <summary>Get excluded category prefixes. Prefers runtime overrides (ExcludedCategoryPrefixesOverrides) when present; otherwise uses defaults (ExcludedCategoryPrefixes).</summary>
+    [HttpGet("filters")]
+    public ActionResult<FiltersResponse> GetFilters()
+    {
+        var prefixes = AppLogsConfigHelper.GetEffectiveExcludedPrefixes(_configuration);
+        return Ok(new FiltersResponse(prefixes));
+    }
+
+    /// <summary>Set excluded category prefixes. Writes to appsettings.Overrides.json and reloads config.</summary>
+    [HttpPost("filters")]
+    public ActionResult<FiltersResponse> SetFilters([FromBody] FiltersRequest request)
+    {
+        var prefixes = request?.ExcludedCategoryPrefixes ?? [];
+        var path = GetOverridesPath();
+        if (!TryUpdateOverrides(path, logLevel: null, excludedPrefixes: prefixes))
+        {
+            _logger.LogError(LogEvents.FiltersSetFailed, "Failed to write filters overrides file to {Path}", path);
+            return StatusCode(500, new { error = "Failed to write overrides file." });
+        }
+
+        _configurationRoot.Reload();
+        _logger.LogInformation(LogEvents.FiltersChanged, "App logs filters updated, count={Count}", prefixes.Count);
+        return Ok(new FiltersResponse(prefixes));
+    }
+
+    /// <summary>Restore filter defaults by removing overrides. Uses ExcludedCategoryPrefixes from appsettings.json.</summary>
+    [HttpPost("filters/restore-defaults")]
+    public ActionResult<FiltersResponse> RestoreFilterDefaults()
+    {
+        var path = GetOverridesPath();
+        if (!TryRemoveFilterOverrides(path))
+        {
+            _logger.LogError(LogEvents.FiltersSetFailed, "Failed to remove filter overrides from {Path}", path);
+            return StatusCode(500, new { error = "Failed to update overrides file." });
+        }
+
+        _configurationRoot.Reload();
+        var defaults = AppLogsConfigHelper.GetDefaultExcludedPrefixes(_configuration);
+        _logger.LogInformation(LogEvents.FiltersChanged, "App logs filters restored to defaults, count={Count}", defaults.Count);
+        return Ok(new FiltersResponse(defaults));
+    }
+
+    private string GetOverridesPath()
+    {
+        var path = _overridesOptions.FilePath?.Trim();
+        return string.IsNullOrEmpty(path)
+            ? Path.Combine(AppContext.BaseDirectory, RuntimeOverridesOptions.DefaultFileName)
+            : path;
+    }
+
+    private bool TryUpdateOverrides(string filePath, LogLevel? logLevel, List<string>? excludedPrefixes)
+    {
+        try
+        {
+            var dir = Path.GetDirectoryName(filePath);
+            if (!string.IsNullOrEmpty(dir))
+                Directory.CreateDirectory(dir);
+
+            var root = LoadOverrides(filePath);
+
+            if (logLevel.HasValue)
+            {
+                root["Logging"] = new JsonObject
+                {
+                    ["LogLevel"] = new JsonObject { ["Default"] = LevelName(logLevel.Value) }
+                };
+            }
+
+            if (excludedPrefixes != null)
+            {
+                // Use sentinel when empty so .NET config returns non-null (empty arrays bind to null)
+                var values = excludedPrefixes.Count == 0
+                    ? new[] { JsonValue.Create(AppLogsConfigHelper.ExplicitlyEmptySentinel) }
+                    : excludedPrefixes.Select(s => JsonValue.Create(s)).ToArray();
+                root["AppLogs"] = new JsonObject
+                {
+                    ["ExcludedCategoryPrefixesOverrides"] = new JsonArray(values)
+                };
+            }
+
+            var json = root.ToJsonString(new JsonSerializerOptions { WriteIndented = true });
+            System.IO.File.WriteAllText(filePath, json);
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private bool TryRemoveFilterOverrides(string filePath)
+    {
+        try
+        {
+            var root = LoadOverrides(filePath);
+            if (root["AppLogs"] is JsonObject appLogs)
+            {
+                appLogs.Remove("ExcludedCategoryPrefixesOverrides");
+                if (appLogs.Count == 0)
+                    root.Remove("AppLogs");
+            }
+
+            var json = root.ToJsonString(new JsonSerializerOptions { WriteIndented = true });
+            System.IO.File.WriteAllText(filePath, json);
+            return true;
+        }
+        catch
+        {
+            return false;
+        }
+    }
+
+    private static JsonObject LoadOverrides(string filePath)
+    {
+        if (!System.IO.File.Exists(filePath))
+            return new JsonObject();
+
+        try
+        {
+            var json = System.IO.File.ReadAllText(filePath);
+            var node = JsonNode.Parse(json);
+            return node as JsonObject ?? new JsonObject();
+        }
+        catch
+        {
+            return new JsonObject();
+        }
+    }
+
+    private static string LevelName(LogLevel level) => level switch
+    {
+        LogLevel.Trace => "Trace",
+        LogLevel.Debug => "Debug",
+        LogLevel.Information => "Information",
+        LogLevel.Warning => "Warning",
+        LogLevel.Error => "Error",
+        LogLevel.Critical => "Critical",
+        _ => "Information"
+    };
+
+    private static LogLevel? ParseLevel(string? value)
+    {
+        if (string.IsNullOrWhiteSpace(value)) return null;
+        return value.Trim() switch
+        {
+            "Trace" => LogLevel.Trace,
+            "Debug" => LogLevel.Debug,
+            "Information" or "Info" => LogLevel.Information,
+            "Warning" or "Warn" => LogLevel.Warning,
+            "Error" => LogLevel.Error,
+            "Critical" => LogLevel.Critical,
+            _ => null
+        };
+    }
+
+    public record LogLevelRequest(string? LogLevel);
+    public record LogLevelResponse(string LogLevel);
+    public record FiltersRequest(List<string>? ExcludedCategoryPrefixes);
+    public record FiltersResponse(List<string> ExcludedCategoryPrefixes);
+}

src/DnsmasqWebUI/Controllers/ReloadController.cs

@@ -1,5 +1,7 @@
+using DnsmasqWebUI.Infrastructure.Logging;
 using DnsmasqWebUI.Infrastructure.Services.Abstractions;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
 
 namespace DnsmasqWebUI.Controllers;
 
@@ -8,10 +10,12 @@ namespace DnsmasqWebUI.Controllers;
 public class ReloadController : ControllerBase
 {
     private readonly IReloadService _reloadService;
+    private readonly ILogger<ReloadController> _logger;
 
-    public ReloadController(IReloadService reloadService)
+    public ReloadController(IReloadService reloadService, ILogger<ReloadController> logger)
     {
         _reloadService = reloadService;
+        _logger = logger;
     }
 
     [HttpPost]
@@ -20,10 +24,12 @@ public class ReloadController : ControllerBase
         try
         {
             var result = await _reloadService.ReloadAsync(ct);
+            _logger.LogInformation(LogEvents.ReloadRequestSuccess, "Reload requested, success={Success}", result.Success);
             return Ok(result);
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.ReloadRequestFailed, ex, "Reload request failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }

src/DnsmasqWebUI/Controllers/StatusController.cs

@@ -1,9 +1,11 @@
-using DnsmasqWebUI.Models.Dnsmasq;
-using DnsmasqWebUI.Models.Dnsmasq.EffectiveConfig;
+using DnsmasqWebUI.Infrastructure.Logging;
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
 using DnsmasqWebUI.Models.Config;
 using DnsmasqWebUI.Models.Contracts;
-using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using DnsmasqWebUI.Models.Dnsmasq;
+using DnsmasqWebUI.Models.Dnsmasq.EffectiveConfig;
 using Microsoft.AspNetCore.Mvc;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 
 namespace DnsmasqWebUI.Controllers;
@@ -15,15 +17,18 @@ public class StatusController : ControllerBase
     private readonly DnsmasqOptions _options;
     private readonly IDnsmasqConfigSetService _configSetService;
     private readonly IProcessRunner _processRunner;
+    private readonly ILogger<StatusController> _logger;
 
     public StatusController(
         IOptions<DnsmasqOptions> options,
         IDnsmasqConfigSetService configSetService,
-        IProcessRunner processRunner)
+        IProcessRunner processRunner,
+        ILogger<StatusController> logger)
     {
         _options = options.Value;
         _configSetService = configSetService;
         _processRunner = processRunner;
+        _logger = logger;
     }
 
     [HttpGet]
@@ -31,6 +36,7 @@ public class StatusController : ControllerBase
     {
         try
         {
+            _logger.LogDebug("Get status");
             var set = await _configSetService.GetConfigSetAsync(ct);
             var effectiveLeasesPath = _configSetService.GetLeasesPath();
             var (effectiveConfig, effectiveConfigSources) = _configSetService.GetEffectiveConfigWithSources();
@@ -98,6 +104,7 @@ public class StatusController : ControllerBase
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.StatusGetFailed, ex, "Get status failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }
@@ -140,6 +147,7 @@ public class StatusController : ControllerBase
 
         try
         {
+            _logger.LogDebug("Get status logs download");
             var fullPath = Path.IsPathRooted(logsPath) ? Path.GetFullPath(logsPath) : Path.GetFullPath(Path.Combine(Directory.GetCurrentDirectory(), logsPath));
             if (!System.IO.File.Exists(fullPath))
                 return NotFound();
@@ -154,6 +162,7 @@ public class StatusController : ControllerBase
         }
         catch (Exception ex)
         {
+            _logger.LogError(LogEvents.StatusLogsDownloadFailed, ex, "Status logs download failed");
             return StatusCode(500, new { error = ex.Message });
         }
     }

src/DnsmasqWebUI/DnsmasqWebUI.csproj

@@ -1,7 +1,7 @@
 <Project Sdk="Microsoft.NET.Sdk.Web">
 
   <PropertyGroup>
-    <TargetFramework>net9.0</TargetFramework>
+    <TargetFramework>net10.0</TargetFramework>
     <Nullable>enable</Nullable>
     <ImplicitUsings>enable</ImplicitUsings>
     <!-- Avoid pre-compressed .br/.gz so MapStaticAssets serves uncompressed files (fixes 0-byte/empty response bug). -->
@@ -10,6 +10,7 @@
   </PropertyGroup>
 
   <ItemGroup>
+    <PackageReference Include="Microsoft.AspNetCore.SignalR.Client" Version="10.0.2" />
     <PackageReference Include="Superpower" Version="3.1.0" />
   </ItemGroup>
 

src/DnsmasqWebUI/Extensions/LoggingBuilderExtensions.cs

@@ -0,0 +1,38 @@
+using System.Threading.Channels;
+using DnsmasqWebUI.Infrastructure.Logging;
+using DnsmasqWebUI.Infrastructure.Services;
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using DnsmasqWebUI.Models.Config;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+
+namespace DnsmasqWebUI.Extensions;
+
+/// <summary>
+/// App logs setup: buffer, channel, and provider.
+/// Encapsulates the wiring that must run before the DI container exists (ILoggerProvider is created during host configuration).
+/// Log level and excluded category prefixes are configured via appsettings.Overrides.json (config source with reloadOnChange).
+/// </summary>
+public static class LoggingBuilderExtensions
+{
+    /// <summary>
+    /// Adds the app logs provider (forwards ILogger output to SignalR) and registers buffer and channel.
+    /// Call before <c>builder.Build()</c>.
+    /// </summary>
+    public static ILoggingBuilder AddAppLogs(this ILoggingBuilder logging, IConfiguration configuration)
+    {
+        var services = logging.Services;
+
+        var buffer = new AppLogsBuffer();
+        var pushChannel = Channel.CreateBounded<byte>(new BoundedChannelOptions(1) { FullMode = BoundedChannelFullMode.DropOldest });
+
+        services.AddSingleton(pushChannel);
+        services.AddSingleton<IAppLogsBuffer>(buffer);
+        services.AddSingleton<ILogsService, LogsService>();
+
+        logging.AddProvider(new AppLogsLoggerProvider(buffer, pushChannel, configuration));
+
+        return logging;
+    }
+}

src/DnsmasqWebUI/Extensions/ServiceCollectionExtensions.cs

@@ -30,6 +30,7 @@ public static class ServiceCollectionExtensions
         services.AddHttpClient<IHostsClient, HostsClient>(DnsmasqApiClientName);
         services.AddHttpClient<IDhcpHostsClient, DhcpHostsClient>(DnsmasqApiClientName);
         services.AddHttpClient<ILeasesClient, LeasesClient>(DnsmasqApiClientName);
+        services.AddHttpClient<ILoggingClient, LoggingClient>(DnsmasqApiClientName);
 
         return services;
     }

src/DnsmasqWebUI/Extensions/WebApplicationExtensions.cs

@@ -20,7 +20,7 @@ public static class WebApplicationExtensions
         app.UseForwardedHeaders(new ForwardedHeadersOptions
         {
             ForwardedHeaders = ForwardedHeaders.XForwardedFor | ForwardedHeaders.XForwardedProto,
-            KnownNetworks = { new Microsoft.AspNetCore.HttpOverrides.IPNetwork(IPAddress.Loopback, 8) },
+            KnownIPNetworks = { new System.Net.IPNetwork(IPAddress.Loopback, 8) },
         });
 
         return app;

src/DnsmasqWebUI/Hubs/LogsHub.cs

@@ -0,0 +1,42 @@
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using Microsoft.AspNetCore.SignalR;
+
+namespace DnsmasqWebUI.Hubs;
+
+/// <summary>
+/// SignalR hub for log streaming. Clients receive DnsmasqLogsUpdate and AppLogsUpdate.
+/// Server push is done via IHubContext; this hub defines methods clients can invoke.
+/// </summary>
+public class LogsHub : Hub
+{
+    private readonly ILogsService _logsService;
+
+    public LogsHub(ILogsService logsService)
+    {
+        _logsService = logsService;
+    }
+
+    /// <summary>
+    /// Client requests dnsmasq logs. Server runs LogsCommand, diffs, and pushes updates.
+    /// </summary>
+    public async Task RequestDnsmasqLogs()
+    {
+        await _logsService.RunAndPushDnsmasqLogsAsync(Context.ConnectionAborted);
+    }
+
+    /// <summary>
+    /// Client requests a snapshot of recent app logs (replace). Used on connect.
+    /// </summary>
+    public async Task RequestAppLogsSnapshot()
+    {
+        await _logsService.PushAppLogsSnapshotAsync(Context.ConnectionAborted);
+    }
+
+    /// <summary>
+    /// Client polls for new app logs (append). Fallback for reconnect/missed pushes.
+    /// </summary>
+    public async Task RequestAppLogsUpdate()
+    {
+        await _logsService.PushAppLogsPendingAsync(Context.ConnectionAborted);
+    }
+}

src/DnsmasqWebUI/Infrastructure/Client/Abstractions/ILoggingClient.cs

@@ -0,0 +1,11 @@
+namespace DnsmasqWebUI.Infrastructure.Client.Abstractions;
+
+/// <summary>Client for runtime logging API (log level and category filters).</summary>
+public interface ILoggingClient
+{
+    Task<string> GetLevelAsync(CancellationToken ct = default);
+    Task<string> SetLevelAsync(string logLevel, CancellationToken ct = default);
+    Task<IReadOnlyList<string>> GetFiltersAsync(CancellationToken ct = default);
+    Task<IReadOnlyList<string>> SetFiltersAsync(IReadOnlyList<string> excludedCategoryPrefixes, CancellationToken ct = default);
+    Task<IReadOnlyList<string>> RestoreFilterDefaultsAsync(CancellationToken ct = default);
+}

src/DnsmasqWebUI/Infrastructure/Client/LoggingClient.cs

@@ -0,0 +1,51 @@
+using System.Net.Http.Json;
+using DnsmasqWebUI.Infrastructure.Client.Abstractions;
+using DnsmasqWebUI.Infrastructure.Helpers.Http;
+
+namespace DnsmasqWebUI.Infrastructure.Client;
+
+public sealed class LoggingClient : ILoggingClient
+{
+    private readonly HttpClient _http;
+
+    public LoggingClient(HttpClient http) => _http = http;
+
+    public async Task<string> GetLevelAsync(CancellationToken ct = default)
+    {
+        var response = await _http.GetFromJsonAsync<LogLevelResponse>("api/logging/level", ApiJsonOptions.ClientOptions, ct);
+        return response?.LogLevel ?? "Information";
+    }
+
+    public async Task<string> SetLevelAsync(string logLevel, CancellationToken ct = default)
+    {
+        var response = await _http.PostAsJsonAsync("api/logging/level", new { logLevel }, ct);
+        response.EnsureSuccessStatusCode();
+        var body = await response.Content.ReadFromJsonAsync<LogLevelResponse>(ApiJsonOptions.ClientOptions, ct);
+        return body?.LogLevel ?? "Information";
+    }
+
+    public async Task<IReadOnlyList<string>> GetFiltersAsync(CancellationToken ct = default)
+    {
+        var response = await _http.GetFromJsonAsync<FiltersResponse>("api/logging/filters", ApiJsonOptions.ClientOptions, ct);
+        return response?.ExcludedCategoryPrefixes ?? [];
+    }
+
+    public async Task<IReadOnlyList<string>> SetFiltersAsync(IReadOnlyList<string> excludedCategoryPrefixes, CancellationToken ct = default)
+    {
+        var response = await _http.PostAsJsonAsync("api/logging/filters", new { excludedCategoryPrefixes }, ct);
+        response.EnsureSuccessStatusCode();
+        var body = await response.Content.ReadFromJsonAsync<FiltersResponse>(ApiJsonOptions.ClientOptions, ct);
+        return body?.ExcludedCategoryPrefixes ?? [];
+    }
+
+    public async Task<IReadOnlyList<string>> RestoreFilterDefaultsAsync(CancellationToken ct = default)
+    {
+        var response = await _http.PostAsync("api/logging/filters/restore-defaults", null, ct);
+        response.EnsureSuccessStatusCode();
+        var body = await response.Content.ReadFromJsonAsync<FiltersResponse>(ApiJsonOptions.ClientOptions, ct);
+        return body?.ExcludedCategoryPrefixes ?? [];
+    }
+
+    private record LogLevelResponse(string LogLevel);
+    private record FiltersResponse(List<string> ExcludedCategoryPrefixes);
+}

src/DnsmasqWebUI/Infrastructure/Logging/AppLogsConfigHelper.cs

@@ -0,0 +1,30 @@
+using Microsoft.Extensions.Configuration;
+
+namespace DnsmasqWebUI.Infrastructure.Logging;
+
+/// <summary>
+/// Helper for resolving app logs config. Uses ExcludedCategoryPrefixesOverrides when present (avoids .NET config array merge);
+/// otherwise falls back to ExcludedCategoryPrefixes from appsettings.json.
+/// Uses a sentinel value when user explicitly clears all filters, since .NET config returns null for empty arrays.
+/// </summary>
+public static class AppLogsConfigHelper
+{
+    private const string OverridesKey = "AppLogs:ExcludedCategoryPrefixesOverrides";
+    private const string DefaultsKey = "AppLogs:ExcludedCategoryPrefixes";
+
+    /// <summary>Sentinel value stored when user clears all filters. Filtered out from results; extremely unlikely to match real categories.</summary>
+    public const string ExplicitlyEmptySentinel = "__AppLogsExplicitlyEmpty__";
+
+    /// <summary>Gets effective excluded category prefixes from configuration.</summary>
+    public static List<string> GetEffectiveExcludedPrefixes(IConfiguration configuration)
+    {
+        var overrides = configuration.GetSection(OverridesKey).Get<List<string>>();
+        if (overrides != null)
+            return overrides.Where(s => s != ExplicitlyEmptySentinel).ToList();
+        return GetDefaultExcludedPrefixes(configuration);
+    }
+
+    /// <summary>Gets default excluded category prefixes from appsettings.json (ignores overrides).</summary>
+    public static List<string> GetDefaultExcludedPrefixes(IConfiguration configuration) =>
+        configuration.GetSection(DefaultsKey).Get<List<string>>() ?? [];
+}

src/DnsmasqWebUI/Infrastructure/Logging/AppLogsLoggerProvider.cs

@@ -0,0 +1,89 @@
+using System.Threading.Channels;
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using Microsoft.Extensions.Configuration;
+using Microsoft.Extensions.Logging;
+
+namespace DnsmasqWebUI.Infrastructure.Logging;
+
+/// <summary>
+/// ILoggerProvider that forwards log entries to IAppLogsBuffer for real-time display.
+/// Signals the push channel when logs are written so the hosted service can push to clients.
+/// Filter is evaluated at Log() time (not CreateLogger) so runtime config changes take effect despite LoggerFactory caching.
+/// </summary>
+public sealed class AppLogsLoggerProvider : ILoggerProvider
+{
+    private readonly IAppLogsBuffer _buffer;
+    private readonly Channel<byte> _pushChannel;
+    private readonly IConfiguration _configuration;
+
+    public AppLogsLoggerProvider(
+        IAppLogsBuffer buffer,
+        Channel<byte> pushChannel,
+        IConfiguration configuration)
+    {
+        _buffer = buffer;
+        _pushChannel = pushChannel;
+        _configuration = configuration;
+    }
+
+    public ILogger CreateLogger(string categoryName) =>
+        new FilteringAppLogsLogger(categoryName, _buffer, _pushChannel, _configuration);
+
+    public void Dispose() { }
+
+    private sealed class FilteringAppLogsLogger : ILogger
+    {
+        private readonly string _category;
+        private readonly IAppLogsBuffer _buffer;
+        private readonly Channel<byte> _pushChannel;
+        private readonly IConfiguration _configuration;
+
+        public FilteringAppLogsLogger(string category, IAppLogsBuffer buffer, Channel<byte> pushChannel, IConfiguration configuration)
+        {
+            _category = category;
+            _buffer = buffer;
+            _pushChannel = pushChannel;
+            _configuration = configuration;
+        }
+
+        public IDisposable? BeginScope<TState>(TState state) where TState : notnull => null;
+
+        public bool IsEnabled(LogLevel logLevel) => logLevel != LogLevel.None;
+
+        public void Log<TState>(LogLevel logLevel, EventId eventId, TState state, Exception? exception, Func<TState, Exception?, string> formatter)
+        {
+            if (IsExcluded(_category))
+                return;
+
+            var msg = formatter(state, exception);
+            var timestamp = DateTime.UtcNow.ToString("yyyy-MM-dd HH:mm:ss.fff");
+            var level = logLevel switch
+            {
+                LogLevel.Trace => "TRC",
+                LogLevel.Debug => "DBG",
+                LogLevel.Information => "INF",
+                LogLevel.Warning => "WRN",
+                LogLevel.Error => "ERR",
+                LogLevel.Critical => "CRT",
+                _ => "???"
+            };
+            var line = $"{timestamp} [{level}] {_category}: {msg}";
+            if (exception != null)
+                line += $"{Environment.NewLine}{exception}";
+            _buffer.Enqueue(line);
+            _pushChannel.Writer.TryWrite(0);
+        }
+
+        private bool IsExcluded(string category)
+        {
+            var prefixes = AppLogsConfigHelper.GetEffectiveExcludedPrefixes(_configuration);
+            if (prefixes.Count == 0) return false;
+            foreach (var prefix in prefixes)
+            {
+                if (!string.IsNullOrEmpty(prefix) && category.StartsWith(prefix, StringComparison.Ordinal))
+                    return true;
+            }
+            return false;
+        }
+    }
+}

src/DnsmasqWebUI/Infrastructure/Logging/LogEvents.cs

@@ -0,0 +1,70 @@
+using Microsoft.Extensions.Logging;
+
+namespace DnsmasqWebUI.Infrastructure.Logging;
+
+/// <summary>Structured event IDs for application logging. Enables filtering and alerting by event type.</summary>
+internal static class LogEvents
+{
+    // Config (1xxx)
+    public static readonly EventId ConfigGetSetFailed = new(1001, nameof(ConfigGetSetFailed));
+    public static readonly EventId ConfigGetManagedFailed = new(1002, nameof(ConfigGetManagedFailed));
+    public static readonly EventId ConfigPutManagedFailed = new(1003, nameof(ConfigPutManagedFailed));
+    public static readonly EventId ConfigPutManagedSuccess = new(1004, nameof(ConfigPutManagedSuccess));
+    public static readonly EventId ConfigNoManagedFilePath = new(1005, nameof(ConfigNoManagedFilePath));
+    public static readonly EventId ConfigWroteManagedFile = new(1006, nameof(ConfigWroteManagedFile));
+
+    // Hosts (2xxx)
+    public static readonly EventId HostsGetFailed = new(2001, nameof(HostsGetFailed));
+    public static readonly EventId HostsGetReadOnlyFailed = new(2002, nameof(HostsGetReadOnlyFailed));
+    public static readonly EventId HostsPutFailed = new(2003, nameof(HostsPutFailed));
+    public static readonly EventId HostsPutValidationFailed = new(2004, nameof(HostsPutValidationFailed));
+    public static readonly EventId HostsPutSuccess = new(2005, nameof(HostsPutSuccess));
+    public static readonly EventId HostsWroteManagedFile = new(2006, nameof(HostsWroteManagedFile));
+
+    // Dhcp (3xxx)
+    public static readonly EventId DhcpGetHostsFailed = new(3001, nameof(DhcpGetHostsFailed));
+    public static readonly EventId DhcpPutHostsFailed = new(3002, nameof(DhcpPutHostsFailed));
+    public static readonly EventId DhcpPutHostsValidationFailed = new(3003, nameof(DhcpPutHostsValidationFailed));
+    public static readonly EventId DhcpPutHostsSuccess = new(3004, nameof(DhcpPutHostsSuccess));
+
+    // Reload (4xxx)
+    public static readonly EventId ReloadRequestFailed = new(4001, nameof(ReloadRequestFailed));
+    public static readonly EventId ReloadRequestSuccess = new(4002, nameof(ReloadRequestSuccess));
+    public static readonly EventId ReloadCommandNotConfigured = new(4003, nameof(ReloadCommandNotConfigured));
+    public static readonly EventId ReloadRejectedConcurrent = new(4004, nameof(ReloadRejectedConcurrent));
+    public static readonly EventId ReloadNonZeroExit = new(4005, nameof(ReloadNonZeroExit));
+    public static readonly EventId ReloadSucceeded = new(4006, nameof(ReloadSucceeded));
+    public static readonly EventId ReloadFailed = new(4007, nameof(ReloadFailed));
+
+    // Status (5xxx)
+    public static readonly EventId StatusGetFailed = new(5001, nameof(StatusGetFailed));
+    public static readonly EventId StatusLogsDownloadFailed = new(5002, nameof(StatusLogsDownloadFailed));
+
+    // Leases (6xxx)
+    public static readonly EventId LeasesGetFailed = new(6001, nameof(LeasesGetFailed));
+
+    // Logging (7xxx)
+    public static readonly EventId LogLevelChanged = new(7001, nameof(LogLevelChanged));
+    public static readonly EventId LogLevelSetBadRequest = new(7002, nameof(LogLevelSetBadRequest));
+    public static readonly EventId LogLevelSetFailed = new(7003, nameof(LogLevelSetFailed));
+    public static readonly EventId FiltersChanged = new(7004, nameof(FiltersChanged));
+    public static readonly EventId FiltersSetFailed = new(7005, nameof(FiltersSetFailed));
+
+    // LogsService (8010)
+    public static readonly EventId DnsmasqLogsPushFailed = new(8010, nameof(DnsmasqLogsPushFailed));
+
+    // ProcessRunner (8xxx)
+    public static readonly EventId CommandFailed = new(8001, nameof(CommandFailed));
+    public static readonly EventId CommandTimeout = new(8002, nameof(CommandTimeout));
+    public static readonly EventId CommandStarted = new(8003, nameof(CommandStarted));
+    public static readonly EventId CommandCompleted = new(8004, nameof(CommandCompleted));
+
+    // LeasesFileService (9xxx)
+    public static readonly EventId LeasesReadSuccess = new(9001, nameof(LeasesReadSuccess));
+
+    // Application lifecycle (9xxx)
+    public static readonly EventId ApplicationStarted = new(9101, nameof(ApplicationStarted));
+    public static readonly EventId ApplicationStopping = new(9102, nameof(ApplicationStopping));
+    public static readonly EventId ManagedConfigConfFileLineSet = new(9110, nameof(ManagedConfigConfFileLineSet));
+    public static readonly EventId ManagedConfigCreatedAtStartup = new(9111, nameof(ManagedConfigCreatedAtStartup));
+}

src/DnsmasqWebUI/Infrastructure/Services/Abstractions/IAppLogsBuffer.cs

@@ -0,0 +1,16 @@
+namespace DnsmasqWebUI.Infrastructure.Services.Abstractions;
+
+/// <summary>
+/// Ring buffer of recent app log lines. Filled by ILoggerProvider, drained for SignalR push.
+/// </summary>
+public interface IAppLogsBuffer
+{
+    /// <summary>Returns up to maxLines most recent lines (oldest first).</summary>
+    IReadOnlyList<string> GetRecent(int maxLines = 500);
+
+    /// <summary>Enqueues a formatted log line. Called by the logging provider.</summary>
+    void Enqueue(string line);
+
+    /// <summary>Returns and clears pending lines for streaming push. Called by pusher.</summary>
+    IReadOnlyList<string> DrainPending();
+}

src/DnsmasqWebUI/Infrastructure/Services/Abstractions/ILogsService.cs

@@ -0,0 +1,24 @@
+namespace DnsmasqWebUI.Infrastructure.Services.Abstractions;
+
+/// <summary>
+/// Runs LogsCommand, diffs output, chunks by lines, and pushes via SignalR.
+/// Triggered by client (RequestDnsmasqLogs) or file watcher when LogsPath changes.
+/// App logs: event-driven push when provider writes; snapshot on connect; poll fallback.
+/// </summary>
+public interface ILogsService
+{
+    /// <summary>
+    /// Runs LogsCommand, diffs against cache, and pushes DnsmasqLogsUpdate to all connected clients.
+    /// </summary>
+    Task RunAndPushDnsmasqLogsAsync(CancellationToken ct = default);
+
+    /// <summary>
+    /// Pushes recent app logs from buffer to all clients (replace). Called when client connects.
+    /// </summary>
+    Task PushAppLogsSnapshotAsync(CancellationToken ct = default);
+
+    /// <summary>
+    /// Pushes pending app log lines as append to all clients. Event-driven from provider; poll fallback.
+    /// </summary>
+    Task PushAppLogsPendingAsync(CancellationToken ct = default);
+}

src/DnsmasqWebUI/Infrastructure/Services/Abstractions/IProcessRunner.cs

@@ -7,4 +7,7 @@ public interface IProcessRunner : IApplicationScopedService
 {
     /// <summary>Runs a shell command with timeout and cancellation. Returns exit code (null if timed out or failed to start), stdout, stderr, and whether the run timed out.</summary>
     Task<ProcessRunResult> RunAsync(string? command, TimeSpan timeout, CancellationToken ct = default);
+
+    /// <summary>Same as RunAsync but caps stdout/stderr length. When exceeded, truncates and appends a notice.</summary>
+    Task<ProcessRunResult> RunAsync(string? command, TimeSpan timeout, int? maxOutputChars, CancellationToken ct = default);
 }

src/DnsmasqWebUI/Infrastructure/Services/AppLogsBuffer.cs

@@ -0,0 +1,43 @@
+namespace DnsmasqWebUI.Infrastructure.Services;
+
+/// <inheritdoc cref="Abstractions.IAppLogsBuffer" />
+public sealed class AppLogsBuffer : Abstractions.IAppLogsBuffer
+{
+    private const int MaxLines = 1000;
+    private readonly List<string> _lines = [];
+    private readonly List<string> _pending = [];
+    private readonly object _lock = new();
+
+    public IReadOnlyList<string> GetRecent(int maxLines = 500)
+    {
+        lock (_lock)
+        {
+            if (_lines.Count <= maxLines)
+                return _lines.ToList();
+            return _lines.TakeLast(maxLines).ToList();
+        }
+    }
+
+    public void Enqueue(string line)
+    {
+        lock (_lock)
+        {
+            _lines.Add(line);
+            _pending.Add(line);
+            while (_lines.Count > MaxLines)
+                _lines.RemoveAt(0);
+        }
+    }
+
+    public IReadOnlyList<string> DrainPending()
+    {
+        lock (_lock)
+        {
+            if (_pending.Count == 0)
+                return [];
+            var copy = _pending.ToList();
+            _pending.Clear();
+            return copy;
+        }
+    }
+}

src/DnsmasqWebUI/Infrastructure/Services/AppLogsPushTriggeredHostedService.cs

@@ -0,0 +1,65 @@
+using System.Threading.Channels;
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace DnsmasqWebUI.Infrastructure.Services;
+
+/// <summary>
+/// Listens for signals from AppLogsLoggerProvider; drains pending app logs and pushes via LogsService.
+/// Event-driven: push happens when logs are written, with a short debounce to batch rapid writes.
+/// </summary>
+public sealed class AppLogsPushTriggeredHostedService : IApplicationHostedService
+{
+    private const int DebounceMs = 50;
+
+    private readonly Channel<byte> _channel;
+    private readonly ILogsService _logsService;
+    private readonly ILogger<AppLogsPushTriggeredHostedService> _logger;
+
+    public AppLogsPushTriggeredHostedService(
+        Channel<byte> appLogsPushChannel,
+        ILogsService logsService,
+        ILogger<AppLogsPushTriggeredHostedService> logger)
+    {
+        _channel = appLogsPushChannel;
+        _logsService = logsService;
+        _logger = logger;
+    }
+
+    public Task StartAsync(CancellationToken ct)
+    {
+        _ = RunLoopAsync(ct);
+        return Task.CompletedTask;
+    }
+
+    public Task StopAsync(CancellationToken ct) => Task.CompletedTask;
+
+    private async Task RunLoopAsync(CancellationToken ct)
+    {
+        try
+        {
+            await foreach (var _ in _channel.Reader.ReadAllAsync(ct))
+            {
+                await Task.Delay(DebounceMs, ct);
+                while (_channel.Reader.TryRead(out byte discarded)) { } // Drain extra signals during debounce
+                try
+                {
+                    await _logsService.PushAppLogsPendingAsync(ct);
+                }
+                catch (OperationCanceledException)
+                {
+                    throw;
+                }
+                catch (Exception ex)
+                {
+                    _logger.LogDebug(ex, "Error pushing app logs");
+                }
+            }
+        }
+        catch (OperationCanceledException)
+        {
+            // Shutdown; ignore
+        }
+    }
+}

src/DnsmasqWebUI/Infrastructure/Services/ApplicationLifecycleLoggingHostedService.cs

@@ -0,0 +1,29 @@
+using DnsmasqWebUI.Infrastructure.Logging;
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace DnsmasqWebUI.Infrastructure.Services;
+
+/// <summary>Logs application started and stopping so the app logs viewer shows lifecycle events.</summary>
+public sealed class ApplicationLifecycleLoggingHostedService : IApplicationHostedService
+{
+    private readonly ILogger<ApplicationLifecycleLoggingHostedService> _logger;
+
+    public ApplicationLifecycleLoggingHostedService(ILogger<ApplicationLifecycleLoggingHostedService> logger)
+    {
+        _logger = logger;
+    }
+
+    public Task StartAsync(CancellationToken cancellationToken)
+    {
+        _logger.LogInformation(LogEvents.ApplicationStarted, "Application started");
+        return Task.CompletedTask;
+    }
+
+    public Task StopAsync(CancellationToken cancellationToken)
+    {
+        _logger.LogInformation(LogEvents.ApplicationStopping, "Application stopping");
+        return Task.CompletedTask;
+    }
+}

src/DnsmasqWebUI/Infrastructure/Services/ClientSettingsService.cs

@@ -12,6 +12,7 @@ namespace DnsmasqWebUI.Infrastructure.Services;
 public sealed class ClientSettingsService : IClientSettingsService, IAsyncDisposable
 {
     private readonly IJSRuntime _jsRuntime;
+    private readonly ILogger<ClientSettingsService> _logger;
     private IJSObjectReference? _module;
     private static readonly JsonSerializerOptions JsonOptions = new()
     {
@@ -20,13 +21,23 @@ public sealed class ClientSettingsService : IClientSettingsService, IAsyncDispos
         WriteIndented = false
     };
 
-    public ClientSettingsService(IJSRuntime jsRuntime) => _jsRuntime = jsRuntime;
+    public ClientSettingsService(IJSRuntime jsRuntime, ILogger<ClientSettingsService> logger)
+    {
+        _jsRuntime = jsRuntime;
+        _logger = logger;
+    }
 
-    private async Task<IJSObjectReference> GetModuleAsync()
+    private async Task<IJSObjectReference?> GetModuleAsync()
     {
         if (_module != null) return _module;
+        try
+        {
             _module = await _jsRuntime.InvokeAsync<IJSObjectReference>(
                 "import", "./js/client-settings-storage.js");
+        }
+        catch (InvalidOperationException ex) { _logger.LogDebug(ex, "JS import skipped: prerender (no JS available)"); return null; }
+        catch (JSDisconnectedException ex) { _logger.LogDebug(ex, "JS import skipped: circuit disconnected"); return null; }
+        catch (JSException ex) { _logger.LogDebug(ex, "JS import failed"); return null; }
         return _module;
     }
 
@@ -34,6 +45,7 @@ public sealed class ClientSettingsService : IClientSettingsService, IAsyncDispos
     public async Task<ClientSettings> LoadSettingsAsync()
     {
         var module = await GetModuleAsync();
+        if (module == null) return new ClientSettings();
         var json = await module.InvokeAsync<string?>("getItem");
         if (string.IsNullOrWhiteSpace(json)) return new ClientSettings();
         try
@@ -49,8 +61,9 @@ public sealed class ClientSettingsService : IClientSettingsService, IAsyncDispos
     /// <inheritdoc />
     public async Task SaveSettingsAsync(ClientSettings settings)
     {
-        var json = JsonSerializer.Serialize(settings, JsonOptions);
         var module = await GetModuleAsync();
+        if (module == null) return;
+        var json = JsonSerializer.Serialize(settings, JsonOptions);
         await module.InvokeVoidAsync("setItem", json);
     }
 
@@ -60,13 +73,10 @@ public sealed class ClientSettingsService : IClientSettingsService, IAsyncDispos
     public async ValueTask DisposeAsync()
     {
         if (_module == null) return;
-        try
-        {
-            await _module.DisposeAsync();
-        }
-        finally
-        {
-            _module = null;
-        }
+        try { await _module.DisposeAsync(); }
+        catch (InvalidOperationException ex) { _logger.LogDebug(ex, "JS module DisposeAsync skipped (prerender)"); }
+        catch (JSDisconnectedException ex) { _logger.LogDebug(ex, "JS module DisposeAsync skipped: circuit disconnected"); }
+        catch (JSException ex) { _logger.LogDebug(ex, "JS module DisposeAsync failed"); }
+        finally { _module = null; }
     }
 }

src/DnsmasqWebUI/Infrastructure/Services/DnsmasqConfigService.cs

@@ -1,12 +1,14 @@
 using System.Text;
 using DnsmasqWebUI.Infrastructure.Helpers.Config;
+using DnsmasqWebUI.Infrastructure.Logging;
+using DnsmasqWebUI.Infrastructure.Parsers;
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
 using DnsmasqWebUI.Models.Config;
 using DnsmasqWebUI.Models.Contracts;
 using DnsmasqWebUI.Models.Dhcp;
 using DnsmasqWebUI.Models.Dnsmasq;
 using DnsmasqWebUI.Models.Dnsmasq.EffectiveConfig;
-using DnsmasqWebUI.Infrastructure.Parsers;
-using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using Microsoft.Extensions.Logging;
 
 namespace DnsmasqWebUI.Infrastructure.Services;
 
@@ -34,7 +36,7 @@ public class DnsmasqConfigService : IDnsmasqConfigService
         var snapshot = await _configSetCache.GetSnapshotAsync(ct);
         if (string.IsNullOrEmpty(snapshot.Set.ManagedFilePath))
         {
-            _logger.LogDebug("No managed file path (no conf-dir in main config); returning empty dhcp hosts");
+            _logger.LogDebug(LogEvents.ConfigNoManagedFilePath, "No managed file path (no conf-dir in main config); returning empty dhcp hosts");
             return Array.Empty<DhcpHostEntry>();
         }
         var allEntries = snapshot.DhcpHostEntries.ToList();
@@ -149,7 +151,7 @@ public class DnsmasqConfigService : IDnsmasqConfigService
         EnsureManagedHostsFileExists(set.ManagedHostsFilePath);
         var effectiveHostsPathDhcp = configLines.OfType<AddnHostsLine>().FirstOrDefault()?.AddnHostsPath ?? "";
         _configSetCache.NotifyWeWroteManagedConfig(new ManagedConfigContent(configLines, effectiveHostsPathDhcp));
-        _logger.LogInformation("Wrote managed config file: {Path}", path);
+        _logger.LogInformation(LogEvents.ConfigWroteManagedFile, "Wrote managed config file: {Path}", path);
     }
 
     /// <summary>Returns MAC -> source file path for all dhcp-host MACs in non-managed config files (for duplicate validation).</summary>
@@ -204,7 +206,7 @@ public class DnsmasqConfigService : IDnsmasqConfigService
         EnsureManagedHostsFileExists(set.ManagedHostsFilePath);
         var effectiveHostsPath = list.OfType<AddnHostsLine>().FirstOrDefault()?.AddnHostsPath ?? "";
         _configSetCache.NotifyWeWroteManagedConfig(new ManagedConfigContent(list, effectiveHostsPath));
-        _logger.LogInformation("Wrote managed config file: {Path}", path);
+        _logger.LogInformation(LogEvents.ConfigWroteManagedFile, "Wrote managed config file: {Path}", path);
     }
 
 }

src/DnsmasqWebUI/Infrastructure/Services/EnsureManagedConfigHostedService.cs

@@ -1,9 +1,11 @@
 using System.Text;
 using DnsmasqWebUI.Infrastructure.Helpers.Config;
-using DnsmasqWebUI.Models.Config;
-using DnsmasqWebUI.Models.Dnsmasq;
+using DnsmasqWebUI.Infrastructure.Logging;
 using DnsmasqWebUI.Infrastructure.Parsers;
 using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using DnsmasqWebUI.Models.Config;
+using DnsmasqWebUI.Models.Dnsmasq;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 
 namespace DnsmasqWebUI.Infrastructure.Services;
@@ -79,7 +81,7 @@ public class EnsureManagedConfigHostedService : IApplicationHostedService
                 lines.Add("");
             lines.Add(confFileLine);
             await File.WriteAllLinesAsync(mainFull, lines, DnsmasqFileEncoding.Utf8NoBom, cancellationToken);
-            _logger.LogInformation("Set {Line} as the last line of main config {Path} so the managed file is included only by conf-file=.", confFileLine, mainFull);
+            _logger.LogInformation(LogEvents.ManagedConfigConfFileLineSet, "Set {Line} as the last line of main config {Path} so the managed file is included only by conf-file=.", confFileLine, mainFull);
         }
         else
         {
@@ -91,7 +93,7 @@ public class EnsureManagedConfigHostedService : IApplicationHostedService
         if (File.Exists(set.ManagedFilePath))
             return;
 
-        _logger.LogInformation("Creating managed config file at startup: {Path}", set.ManagedFilePath);
+        _logger.LogInformation(LogEvents.ManagedConfigCreatedAtStartup, "Creating managed config file at startup: {Path}", set.ManagedFilePath);
         await configService.WriteManagedConfigAsync(Array.Empty<DnsmasqConfLine>(), cancellationToken);
     }
 

src/DnsmasqWebUI/Infrastructure/Services/HostsFileService.cs

@@ -1,7 +1,9 @@
 using DnsmasqWebUI.Infrastructure.Helpers.Config;
-using DnsmasqWebUI.Models.Hosts;
+using DnsmasqWebUI.Infrastructure.Logging;
 using DnsmasqWebUI.Infrastructure.Parsers;
 using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using DnsmasqWebUI.Models.Hosts;
+using Microsoft.Extensions.Logging;
 
 namespace DnsmasqWebUI.Infrastructure.Services;
 
@@ -39,6 +41,6 @@ public class HostsFileService : IHostsFileService
         await File.WriteAllLinesAsync(tmpPath, lines, DnsmasqFileEncoding.Utf8NoBom, ct);
         File.Move(tmpPath, path, overwrite: true);
         _hostsCache.NotifyWeWroteManagedHosts(entries);
-        _logger.LogInformation("Wrote managed hosts file: {Path}", path);
+        _logger.LogInformation(LogEvents.HostsWroteManagedFile, "Wrote managed hosts file: {Path}", path);
     }
 }

src/DnsmasqWebUI/Infrastructure/Services/LeasesFileService.cs

@@ -1,15 +1,19 @@
-using DnsmasqWebUI.Models.Dhcp;
+using DnsmasqWebUI.Infrastructure.Logging;
 using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using DnsmasqWebUI.Models.Dhcp;
+using Microsoft.Extensions.Logging;
 
 namespace DnsmasqWebUI.Infrastructure.Services;
 
 public class LeasesFileService : ILeasesFileService
 {
     private readonly ILeasesCache _cache;
+    private readonly ILogger<LeasesFileService> _logger;
 
-    public LeasesFileService(ILeasesCache cache)
+    public LeasesFileService(ILeasesCache cache, ILogger<LeasesFileService> logger)
     {
         _cache = cache;
+        _logger = logger;
     }
 
     public async Task<IReadOnlyList<LeaseEntry>> ReadAsync(CancellationToken ct = default)
@@ -19,5 +23,10 @@ public class LeasesFileService : ILeasesFileService
     }
 
     public async Task<(bool Available, IReadOnlyList<LeaseEntry>? Entries)> TryReadAsync(CancellationToken ct = default)
-        => await _cache.GetOrRefreshAsync(ct);
+    {
+        var (available, entries) = await _cache.GetOrRefreshAsync(ct);
+        if (available && entries != null)
+            _logger.LogInformation(LogEvents.LeasesReadSuccess, "Leases read, count={Count}", entries.Count);
+        return (available, entries);
+    }
 }

src/DnsmasqWebUI/Infrastructure/Services/LogsFileWatcherHostedService.cs

@@ -0,0 +1,141 @@
+using DnsmasqWebUI.Models.Dnsmasq.EffectiveConfig;
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using Microsoft.Extensions.Hosting;
+using Microsoft.Extensions.Logging;
+
+namespace DnsmasqWebUI.Infrastructure.Services;
+
+/// <summary>
+/// When LogsPath is set in effective config, watches that file and triggers LogsService push on change.
+/// Polling remains the primary mechanism; this is a best-effort optimization.
+/// </summary>
+public sealed class LogsFileWatcherHostedService : IApplicationHostedService
+{
+    private const int ResolveIntervalSeconds = 60;
+
+    private readonly IDnsmasqConfigSetService _configSetService;
+    private readonly ILogsService _logsService;
+    private readonly ILogger<LogsFileWatcherHostedService> _logger;
+    private FileSystemWatcher? _watcher;
+    private string? _currentPath;
+    private readonly object _lock = new();
+
+    public LogsFileWatcherHostedService(
+        IDnsmasqConfigSetService configSetService,
+        ILogsService logsService,
+        ILogger<LogsFileWatcherHostedService> logger)
+    {
+        _configSetService = configSetService;
+        _logsService = logsService;
+        _logger = logger;
+    }
+
+    public Task StartAsync(CancellationToken ct)
+    {
+        _ = RunLoopAsync(ct);
+        return Task.CompletedTask;
+    }
+
+    public Task StopAsync(CancellationToken ct) => Task.CompletedTask;
+
+    private async Task RunLoopAsync(CancellationToken ct)
+    {
+        while (!ct.IsCancellationRequested)
+        {
+            try
+            {
+                var (effectiveConfig, _) = _configSetService.GetEffectiveConfigWithSources();
+                var logsPath = EffectiveDnsmasqConfig.GetLogsPath(effectiveConfig);
+                UpdateWatcher(logsPath);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogDebug(ex, "Error resolving LogsPath for file watcher");
+            }
+
+            try
+            {
+                await Task.Delay(TimeSpan.FromSeconds(ResolveIntervalSeconds), ct);
+            }
+            catch (OperationCanceledException)
+            {
+                break;
+            }
+        }
+
+        lock (_lock)
+        {
+            _watcher?.Dispose();
+            _watcher = null;
+            _currentPath = null;
+        }
+    }
+
+    private void UpdateWatcher(string? logsPath)
+    {
+        var normalized = string.IsNullOrEmpty(logsPath) ? null : Path.GetFullPath(logsPath.Trim());
+
+        lock (_lock)
+        {
+            if (string.Equals(_currentPath, normalized, StringComparison.Ordinal))
+                return;
+
+            _watcher?.Dispose();
+            _watcher = null;
+            _currentPath = normalized;
+
+            if (string.IsNullOrEmpty(normalized))
+            {
+                _logger.LogDebug("Logs path not set; no file watcher");
+                return;
+            }
+
+            var dir = Path.GetDirectoryName(normalized);
+            var fileName = Path.GetFileName(normalized);
+            if (string.IsNullOrEmpty(dir) || string.IsNullOrEmpty(fileName))
+            {
+                _logger.LogDebug("Invalid logs path for watcher: {Path}", normalized);
+                return;
+            }
+
+            try
+            {
+                if (!Directory.Exists(dir))
+                {
+                    _logger.LogDebug("Logs directory does not exist yet: {Dir}", dir);
+                    return;
+                }
+
+                _watcher = new FileSystemWatcher(dir)
+                {
+                    Filter = fileName,
+                    NotifyFilter = NotifyFilters.LastWrite | NotifyFilters.Size
+                };
+                _watcher.Changed += OnFileChanged;
+                _watcher.EnableRaisingEvents = true;
+                _logger.LogDebug("Watching logs file: {Path}", normalized);
+            }
+            catch (Exception ex)
+            {
+                _logger.LogWarning(ex, "Could not create file watcher for logs: {Path}", normalized);
+            }
+        }
+    }
+
+    private void OnFileChanged(object sender, FileSystemEventArgs e)
+    {
+        _ = InvokePushAsync();
+    }
+
+    private async Task InvokePushAsync()
+    {
+        try
+        {
+            await _logsService.RunAndPushDnsmasqLogsAsync(CancellationToken.None);
+        }
+        catch (Exception ex)
+        {
+            _logger.LogDebug(ex, "Error pushing logs on file change");
+        }
+    }
+}

src/DnsmasqWebUI/Infrastructure/Services/LogsService.cs

@@ -0,0 +1,202 @@
+using System.Text;
+using DnsmasqWebUI.Infrastructure.Logging;
+using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using DnsmasqWebUI.Models.Config;
+using DnsmasqWebUI.Models.Logs;
+using Microsoft.AspNetCore.SignalR;
+using Microsoft.Extensions.DependencyInjection;
+using Microsoft.Extensions.Logging;
+using Microsoft.Extensions.Options;
+
+namespace DnsmasqWebUI.Infrastructure.Services;
+
+/// <summary>
+/// Runs LogsCommand, diffs against cache, chunks by lines, and pushes via SignalR.
+/// </summary>
+public sealed class LogsService : ILogsService
+{
+    /// <summary>Max chars from command output before truncation.</summary>
+    private const int MaxCommandOutputChars = 512 * 1024;
+
+    /// <summary>Max bytes per SignalR message (under 32KB default).</summary>
+    private const int MaxMessageContentBytes = 28 * 1024;
+
+    private readonly IHubContext<Hubs.LogsHub> _hubContext;
+    private readonly IServiceScopeFactory _scopeFactory;
+    private readonly IOptions<DnsmasqOptions> _options;
+    private readonly IAppLogsBuffer _appLogsBuffer;
+    private readonly ILogger<LogsService> _logger;
+    private readonly object _dnsmasqLock = new();
+    private string _lastDnsmasqOutput = "";
+
+    public LogsService(
+        IHubContext<Hubs.LogsHub> hubContext,
+        IServiceScopeFactory scopeFactory,
+        IOptions<DnsmasqOptions> options,
+        IAppLogsBuffer appLogsBuffer,
+        ILogger<LogsService> logger)
+    {
+        _hubContext = hubContext;
+        _scopeFactory = scopeFactory;
+        _options = options;
+        _appLogsBuffer = appLogsBuffer;
+        _logger = logger;
+    }
+
+    public async Task RunAndPushDnsmasqLogsAsync(CancellationToken ct = default)
+    {
+        var cmd = _options.Value.LogsCommand?.Trim();
+        if (string.IsNullOrEmpty(cmd))
+            return;
+
+        try
+        {
+            using var scope = _scopeFactory.CreateScope();
+            var processRunner = scope.ServiceProvider.GetRequiredService<IProcessRunner>();
+            var result = await processRunner.RunAsync(cmd, TimeSpan.FromSeconds(10), MaxCommandOutputChars, ct);
+            var raw = result.Stdout + (result.TimedOut ? "\n(Command timed out.)" : "");
+
+            string mode;
+            string content;
+            lock (_dnsmasqLock)
+            {
+                var (m, c) = ComputeDelta(_lastDnsmasqOutput, raw);
+                _lastDnsmasqOutput = raw;
+                mode = m;
+                content = c;
+            }
+
+            if (string.IsNullOrEmpty(content) && mode == "append")
+                return;
+
+            await PushChunkedAsync("DnsmasqLogsUpdate", mode, content, ct);
+        }
+        catch (OperationCanceledException)
+        {
+            throw;
+        }
+        catch (Exception ex)
+        {
+            _logger.LogWarning(LogEvents.DnsmasqLogsPushFailed, ex, "Failed to run or push dnsmasq logs");
+            await PushChunkedAsync("DnsmasqLogsUpdate", "replace", $"(Error: {ex.Message})\n", ct);
+        }
+    }
+
+    public async Task PushAppLogsSnapshotAsync(CancellationToken ct = default)
+    {
+        var lines = _appLogsBuffer.GetRecent(maxLines: 1000);
+        if (lines.Count == 0)
+            return;
+
+        var content = string.Join("\n", lines);
+        if (!string.IsNullOrEmpty(content) && !content.EndsWith('\n'))
+            content += "\n";
+
+        await PushChunkedAsync("AppLogsUpdate", "replace", content, ct);
+    }
+
+    public async Task PushAppLogsPendingAsync(CancellationToken ct = default)
+    {
+        var lines = _appLogsBuffer.DrainPending();
+        if (lines.Count == 0)
+            return;
+
+        var content = string.Join("\n", lines);
+        if (!string.IsNullOrEmpty(content) && !content.EndsWith('\n'))
+            content += "\n";
+
+        await PushChunkedAsync("AppLogsUpdate", "append", content, ct);
+    }
+
+    private static (string mode, string content) ComputeDelta(string oldOutput, string newOutput)
+    {
+        if (string.IsNullOrEmpty(oldOutput))
+            return ("replace", newOutput);
+
+        var oldLines = oldOutput.Split('\n');
+        var newLines = newOutput.Split('\n');
+
+        // Find longest suffix of old that matches prefix of new (tail-style overlap)
+        var maxOverlap = Math.Min(oldLines.Length, newLines.Length);
+        var overlap = 0;
+        for (var k = 1; k <= maxOverlap; k++)
+        {
+            var match = true;
+            for (var i = 0; i < k && match; i++)
+            {
+                if (oldLines[oldLines.Length - k + i] != newLines[i])
+                    match = false;
+            }
+            if (match)
+                overlap = k;
+        }
+
+        if (overlap == 0 || overlap >= newLines.Length)
+            return ("replace", newOutput);
+
+        var newOnly = newLines[overlap..];
+        var content = string.Join("\n", newOnly);
+        if (!string.IsNullOrEmpty(content) && !content.EndsWith('\n'))
+            content += "\n";
+
+        return ("append", content);
+    }
+
+    private async Task PushChunkedAsync(string method, string mode, string content, CancellationToken ct)
+    {
+        var chunks = ChunkByLines(content, MaxMessageContentBytes);
+        for (var i = 0; i < chunks.Count; i++)
+        {
+            var payload = new LogsUpdatePayload(i == 0 ? mode : "append", chunks[i]);
+            await _hubContext.Clients.All.SendAsync(method, payload, ct);
+        }
+    }
+
+    private static List<string> ChunkByLines(string content, int maxBytesPerChunk)
+    {
+        if (string.IsNullOrEmpty(content))
+            return [];
+
+        var lines = content.Split('\n');
+        var chunks = new List<string>();
+        var current = new StringBuilder();
+        var enc = Encoding.UTF8;
+
+        for (var i = 0; i < lines.Length; i++)
+        {
+            var line = lines[i];
+            var lineWithNewline = i < lines.Length - 1 ? line + "\n" : (line.Length > 0 ? line + "\n" : line);
+            var lineBytes = enc.GetByteCount(lineWithNewline);
+
+            if (lineBytes > maxBytesPerChunk)
+            {
+                if (current.Length > 0)
+                {
+                    chunks.Add(current.ToString());
+                    current.Clear();
+                }
+                var trunc = line.Length;
+                while (trunc > 0 && enc.GetByteCount(line[..trunc] + "... (line truncated)\n") > maxBytesPerChunk)
+                    trunc--;
+                chunks.Add((trunc > 0 ? line[..trunc] : line) + "... (line truncated)\n");
+                continue;
+            }
+
+            if (current.Length > 0 && enc.GetByteCount(current.ToString()) + lineBytes > maxBytesPerChunk)
+            {
+                chunks.Add(current.ToString());
+                current.Clear();
+            }
+
+            if (i < lines.Length - 1)
+                current.Append(line).Append('\n');
+            else if (line.Length > 0)
+                current.Append(line).Append('\n');
+        }
+
+        if (current.Length > 0)
+            chunks.Add(current.ToString());
+
+        return chunks;
+    }
+}

src/DnsmasqWebUI/Infrastructure/Services/ProcessRunner.cs

@@ -1,7 +1,8 @@
 using System.Diagnostics;
 using System.Text;
-using DnsmasqWebUI.Models.Contracts;
+using DnsmasqWebUI.Infrastructure.Logging;
 using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using DnsmasqWebUI.Models.Contracts;
 using Microsoft.Extensions.Logging;
 
 namespace DnsmasqWebUI.Infrastructure.Services;
@@ -9,15 +10,24 @@ namespace DnsmasqWebUI.Infrastructure.Services;
 /// <summary>Runs shell commands via /bin/sh with async output capture and timeout. Used by StatusController and ReloadService.</summary>
 public sealed class ProcessRunner : IProcessRunner
 {
+    private const int MaxCommandPrefixLength = 80;
+
     private readonly ILogger<ProcessRunner> _logger;
 
     public ProcessRunner(ILogger<ProcessRunner> logger) => _logger = logger;
 
-    public async Task<ProcessRunResult> RunAsync(string? command, TimeSpan timeout, CancellationToken ct = default)
+    public Task<ProcessRunResult> RunAsync(string? command, TimeSpan timeout, CancellationToken ct = default) =>
+        RunAsync(command, timeout, null, ct);
+
+    public async Task<ProcessRunResult> RunAsync(string? command, TimeSpan timeout, int? maxOutputChars, CancellationToken ct = default)
     {
         if (string.IsNullOrWhiteSpace(command))
             return new ProcessRunResult(null, "", "", false);
 
+        var trimmed = command!.Trim();
+        var prefix = trimmed.Length <= MaxCommandPrefixLength ? trimmed : trimmed[..MaxCommandPrefixLength] + "...";
+        _logger.LogDebug(LogEvents.CommandStarted, "Running command (length={Length}, timeout={Timeout}s): {CommandPrefix}", trimmed.Length, timeout.TotalSeconds, prefix);
+
         var stdout = new StringBuilder();
         var stderr = new StringBuilder();
         using var process = new Process
@@ -33,8 +43,31 @@ public sealed class ProcessRunner : IProcessRunner
             }
         };
 
-        process.OutputDataReceived += (_, e) => { if (e.Data != null) stdout.AppendLine(e.Data); };
-        process.ErrorDataReceived += (_, e) => { if (e.Data != null) stderr.AppendLine(e.Data); };
+        var truncMsg = "\n\n(output truncated)\n";
+        process.OutputDataReceived += (_, e) =>
+        {
+            if (e.Data == null) return;
+            if (maxOutputChars.HasValue && stdout.Length >= maxOutputChars.Value) return;
+            stdout.AppendLine(e.Data);
+            if (maxOutputChars.HasValue && stdout.Length > maxOutputChars.Value)
+            {
+                var keep = Math.Max(0, maxOutputChars.Value - truncMsg.Length);
+                stdout.Length = keep;
+                stdout.Append(truncMsg);
+            }
+        };
+        process.ErrorDataReceived += (_, e) =>
+        {
+            if (e.Data == null) return;
+            if (maxOutputChars.HasValue && stderr.Length >= maxOutputChars.Value) return;
+            stderr.AppendLine(e.Data);
+            if (maxOutputChars.HasValue && stderr.Length > maxOutputChars.Value)
+            {
+                var keep = Math.Max(0, maxOutputChars.Value - truncMsg.Length);
+                stderr.Length = keep;
+                stderr.Append(truncMsg);
+            }
+        };
 
         try
         {
@@ -50,7 +83,7 @@ public sealed class ProcessRunner : IProcessRunner
             }
             catch (OperationCanceledException) when (timeoutCts.IsCancellationRequested && !ct.IsCancellationRequested)
             {
-                _logger.LogWarning("Command timed out after {Timeout}s", timeout.TotalSeconds);
+                _logger.LogWarning(LogEvents.CommandTimeout, "Command timed out after {Timeout}s", timeout.TotalSeconds);
                 try { process.Kill(); } catch { /* best effort */ }
                 var err = stderr.ToString();
                 if (!string.IsNullOrEmpty(err)) err += "\n";
@@ -58,15 +91,17 @@ public sealed class ProcessRunner : IProcessRunner
                 return new ProcessRunResult(null, stdout.ToString(), err, true);
             }
 
+            var exitCode = process.HasExited ? process.ExitCode : -1;
+            _logger.LogDebug(LogEvents.CommandCompleted, "Command completed, exit code={ExitCode}", exitCode);
             return new ProcessRunResult(
-                process.HasExited ? process.ExitCode : -1,
+                exitCode,
                 stdout.ToString(),
                 stderr.ToString(),
                 false);
         }
         catch (Exception ex)
         {
-            _logger.LogError(ex, "Failed to run command");
+            _logger.LogError(LogEvents.CommandFailed, ex, "Failed to run command");
             return new ProcessRunResult(null, "", "", false, ex.Message);
         }
     }

src/DnsmasqWebUI/Infrastructure/Services/ReloadService.cs

@@ -1,5 +1,7 @@
-using DnsmasqWebUI.Models.Config;
+using DnsmasqWebUI.Infrastructure.Logging;
 using DnsmasqWebUI.Infrastructure.Services.Abstractions;
+using DnsmasqWebUI.Models.Config;
+using Microsoft.Extensions.Logging;
 using Microsoft.Extensions.Options;
 
 namespace DnsmasqWebUI.Infrastructure.Services;
@@ -22,13 +24,13 @@ public class ReloadService : IReloadService
     {
         if (string.IsNullOrWhiteSpace(_options.ReloadCommand))
         {
-            _logger.LogDebug("Reload command not configured");
+            _logger.LogDebug(LogEvents.ReloadCommandNotConfigured, "Reload command not configured");
             return new ReloadResult(true, 0, null, "Reload command not configured");
         }
 
         if (!await _reloadLock.WaitAsync(TimeSpan.Zero, ct))
         {
-            _logger.LogDebug("Reload already in progress, rejecting concurrent request");
+            _logger.LogDebug(LogEvents.ReloadRejectedConcurrent, "Reload already in progress, rejecting concurrent request");
             return new ReloadResult(false, -1, null, "Reload already in progress.");
         }
 
@@ -42,9 +44,9 @@ public class ReloadService : IReloadService
                 stderr = (string.IsNullOrEmpty(stderr) ? "" : stderr + "\n") + result.ExceptionMessage;
 
             if (result.ExitCode != 0 && result.ExitCode.HasValue)
-                _logger.LogWarning("Reload command exited with {ExitCode}: {Stderr}", result.ExitCode.Value, stderr);
+                _logger.LogWarning(LogEvents.ReloadNonZeroExit, "Reload command exited with {ExitCode}: {Stderr}", result.ExitCode.Value, stderr);
             else if (result.ExitCode == 0)
-                _logger.LogInformation("Reload command succeeded");
+                _logger.LogInformation(LogEvents.ReloadSucceeded, "Reload command succeeded");
 
             return new ReloadResult(
                 result.ExitCode == 0,
@@ -54,7 +56,7 @@ public class ReloadService : IReloadService
         }
         catch (Exception ex)
         {
-            _logger.LogError(ex, "Failed to run reload command");
+            _logger.LogError(LogEvents.ReloadFailed, ex, "Failed to run reload command");
             return new ReloadResult(false, -1, null, ex.Message);
         }
         finally

src/DnsmasqWebUI/Models/Client/ClientSettings.cs

@@ -8,9 +8,24 @@ public class ClientSettings
     /// <summary>Polling interval for the service status block (seconds).</summary>
     public int ServiceStatusPollingIntervalSeconds { get; set; } = 15;
 
-    /// <summary>Polling interval for the recent logs block (seconds).</summary>
+    /// <summary>Polling interval for the recent dnsmasq logs block (seconds).</summary>
     public int RecentLogsPollingIntervalSeconds { get; set; } = 5;
 
+    /// <summary>Polling interval for the app logs block fallback (seconds).</summary>
+    public int AppLogsPollingIntervalSeconds { get; set; } = 5;
+
     /// <summary>Polling interval for the DHCP leases list (seconds).</summary>
     public int LeasesPollingIntervalSeconds { get; set; } = 5;
+
+    /// <summary>Maximum number of lines in the dnsmasq (recent) logs panel. Older lines are truncated.</summary>
+    public int RecentLogsMaxLines { get; set; } = 500;
+
+    /// <summary>Whether to auto-scroll the dnsmasq logs panel when new lines arrive.</summary>
+    public bool RecentLogsAutoScroll { get; set; } = true;
+
+    /// <summary>Maximum number of lines in the app logs panel. Older lines are truncated.</summary>
+    public int AppLogsMaxLines { get; set; } = 500;
+
+    /// <summary>Whether to auto-scroll the app logs panel when new lines arrive.</summary>
+    public bool AppLogsAutoScroll { get; set; } = true;
 }

src/DnsmasqWebUI/Models/Client/ClientSettingsFields.cs

@@ -0,0 +1,23 @@
+namespace DnsmasqWebUI.Models.Client;
+
+/// <summary>
+/// Per-field metadata for client settings: bounds, display names for validation errors.
+/// Used by SettingsModal (validation on save) and by pages/components (defensive clamp when loading from storage).
+/// </summary>
+public static class ClientSettingsFields
+{
+    public sealed record FieldBounds(int Min, int Max, string DisplayName)
+    {
+        public bool IsValid(int value) => value >= Min && value <= Max;
+        public int Clamp(int value) => Math.Clamp(value, Min, Max);
+        public string? Validate(int value) =>
+            IsValid(value) ? null : $"{DisplayName} must be between {Min} and {Max} seconds. You entered {value}.";
+    }
+
+    public static readonly FieldBounds ServiceStatusPollingInterval = new(5, 300, "Service status polling interval");
+    public static readonly FieldBounds RecentLogsPollingInterval = new(5, 300, "Recent logs polling interval");
+    public static readonly FieldBounds AppLogsPollingInterval = new(5, 300, "App logs polling interval");
+    public static readonly FieldBounds LeasesPollingInterval = new(5, 300, "DHCP leases refresh interval");
+    public static readonly FieldBounds RecentLogsMaxLines = new(100, 2000, "Recent logs max lines");
+    public static readonly FieldBounds AppLogsMaxLines = new(100, 2000, "App logs max lines");
+}

src/DnsmasqWebUI/Models/Client/SettingsModalSections.cs

@@ -11,9 +11,12 @@ public enum SettingsModalContext
     /// <summary>Show only service status polling interval.</summary>
     ServicePolling,
 
-    /// <summary>Show only recent logs polling interval.</summary>
+    /// <summary>Show only recent dnsmasq logs polling interval.</summary>
     LogsPolling,
 
+    /// <summary>Show only app logs polling interval.</summary>
+    AppLogsPolling,
+
     /// <summary>Show only DHCP leases refresh interval.</summary>
     LeasesPolling
 }
@@ -25,7 +28,10 @@ public static class SettingsModalSections
 {
     public const string ServiceStatus = "ServiceStatus";
     public const string Logs = "Logs";
+    public const string AppLogs = "AppLogs";
     public const string Leases = "Leases";
+    public const string RecentLogsDisplay = "RecentLogsDisplay";
+    public const string AppLogsDisplay = "AppLogsDisplay";
 
     /// <summary>Section metadata: display name (header), field label (for input), and searchable text for filtering.</summary>
     public sealed record SectionMeta(string DisplayName, string FieldLabel, string SearchableText);
@@ -33,19 +39,30 @@ public static class SettingsModalSections
     public static readonly IReadOnlyDictionary<string, SectionMeta> All = new Dictionary<string, SectionMeta>(StringComparer.OrdinalIgnoreCase)
     {
         [ServiceStatus] = new("Service status", "Polling interval (seconds)", "service status polling interval seconds"),
-        [Logs] = new("Recent logs", "Polling interval (seconds)", "recent logs polling interval seconds"),
+        [Logs] = new("Recent logs", "Polling interval (seconds)", "recent dnsmasq logs polling interval seconds"),
+        [AppLogs] = new("App logs", "Polling interval (seconds)", "app logs polling interval seconds"),
         [Leases] = new("DHCP leases", "Refresh interval (seconds)", "dhcp leases refresh interval seconds"),
+        [RecentLogsDisplay] = new("Recent logs display", "Max lines / Auto-scroll", "recent logs display max lines auto scroll"),
+        [AppLogsDisplay] = new("App logs display", "Max lines / Auto-scroll", "app logs display max lines auto scroll"),
     };
 
-    /// <summary>Maps a focused context (single-section view) to its section key. Returns null for All.</summary>
-    public static string? GetSectionKeyForContext(SettingsModalContext context) => context switch
+    /// <summary>Maps a focused context (single-section view) to its section keys. Returns null for All (search mode).</summary>
+    public static string[]? GetSectionKeysForContext(SettingsModalContext context) => context switch
     {
-        SettingsModalContext.ServicePolling => ServiceStatus,
-        SettingsModalContext.LogsPolling => Logs,
-        SettingsModalContext.LeasesPolling => Leases,
+        SettingsModalContext.ServicePolling => [ServiceStatus],
+        SettingsModalContext.LogsPolling => [Logs, RecentLogsDisplay],
+        SettingsModalContext.AppLogsPolling => [AppLogs, AppLogsDisplay],
+        SettingsModalContext.LeasesPolling => [Leases],
         _ => null
     };
 
+    /// <summary>Legacy: returns first section key for context. Use GetSectionKeysForContext for multi-section support.</summary>
+    public static string? GetSectionKeyForContext(SettingsModalContext context)
+    {
+        var keys = GetSectionKeysForContext(context);
+        return keys is { Length: > 0 } ? keys[0] : null;
+    }
+
     public static bool MatchesSearch(string key, string searchTerm)
     {
         if (string.IsNullOrWhiteSpace(searchTerm)) return true;

src/DnsmasqWebUI/Models/Config/AppLogsOptions.cs

@@ -0,0 +1,27 @@
+namespace DnsmasqWebUI.Models.Config;
+
+/// <summary>
+/// Configuration for the app logs UI: which logger categories to exclude from the live display.
+/// Bound from "AppLogs" config section (appsettings.json, appsettings.Overrides.json, or AppLogs__* env vars).
+/// </summary>
+public class AppLogsOptions
+{
+    /// <summary>Configuration section name.</summary>
+    public const string SectionName = "AppLogs";
+
+    /// <summary>
+    /// Logger category name prefixes to exclude from the app logs display.
+    /// Any category that starts with one of these strings will not be forwarded to the buffer.
+    /// Defaults exclude noisy framework categories: Components, Kestrel, HttpClient, etc.
+    /// </summary>
+    public List<string> ExcludedCategoryPrefixes { get; set; } =
+    [
+        "Microsoft.AspNetCore.Components.",
+        "Microsoft.AspNetCore.Server.Kestrel.Transport.",
+        "Microsoft.AspNetCore.Server.Kestrel.Connections",
+        "System.Net.Http.",
+        "Microsoft.Extensions.Http.",
+        "Microsoft.AspNetCore.Hosting.",
+        "Microsoft.AspNetCore.Routing.",
+    ];
+}

src/DnsmasqWebUI/Models/Config/RuntimeOverridesOptions.cs

@@ -0,0 +1,19 @@
+namespace DnsmasqWebUI.Models.Config;
+
+/// <summary>
+/// Path for the app settings overrides file used to persist runtime config changes
+/// (e.g. log level). Bound from "RuntimeOverrides" config section.
+/// </summary>
+public class RuntimeOverridesOptions
+{
+    public const string SectionName = "RuntimeOverrides";
+
+    /// <summary>Default filename when FilePath is not set (resolved relative to application base directory).</summary>
+    public const string DefaultFileName = "appsettings.Overrides.json";
+
+    /// <summary>
+    /// Full path to the JSON file the app reads/writes for runtime overrides.
+    /// If not set, defaults to <see cref="DefaultFileName"/> in the application base directory.
+    /// </summary>
+    public string? FilePath { get; set; }
+}

src/DnsmasqWebUI/Models/Logs/LogsUpdatePayload.cs

@@ -0,0 +1,13 @@
+namespace DnsmasqWebUI.Models.Logs;
+
+/// <summary>
+/// Payload sent via SignalR for log updates. Content is chunked by complete lines, max ~28KB per message.
+/// </summary>
+public sealed record LogsUpdatePayload(string Mode, string Content)
+{
+    /// <summary>"append" = add to existing; "replace" = clear then set.</summary>
+    public string Mode { get; } = Mode;
+
+    /// <summary>One or more complete lines. Never split mid-line.</summary>
+    public string Content { get; } = Content;
+}

src/DnsmasqWebUI/Program.cs

@@ -1,4 +1,5 @@
 using DnsmasqWebUI.Components;
+using DnsmasqWebUI.Hubs;
 using DnsmasqWebUI.Models.Config;
 using DnsmasqWebUI.Extensions;
 using DnsmasqWebUI.Infrastructure.Helpers.Http;
@@ -12,9 +13,19 @@ var builder = isDevelopment
     ? WebApplication.CreateBuilder(args)
     : WebApplication.CreateBuilder(new WebApplicationOptions { ContentRootPath = AppContext.BaseDirectory.TrimEnd(Path.DirectorySeparatorChar, Path.AltDirectorySeparatorChar), Args = args });
 
+// Runtime overrides file (Logging.LogLevel.Default, etc.) — add as config source so startup uses actual log level.
+var overridesPath = builder.Configuration["RuntimeOverrides:FilePath"]?.Trim();
+if (string.IsNullOrEmpty(overridesPath))
+    overridesPath = Path.Combine(AppContext.BaseDirectory, RuntimeOverridesOptions.DefaultFileName);
+builder.Configuration.AddJsonFile(overridesPath, optional: true, reloadOnChange: true);
+
 // ---- Application options (title, etc.) ----
 builder.Services.AddOptions<ApplicationOptions>()
     .Bind(builder.Configuration.GetSection(ApplicationOptions.SectionName));
+builder.Services.AddOptions<AppLogsOptions>()
+    .Bind(builder.Configuration.GetSection(AppLogsOptions.SectionName));
+builder.Services.AddOptions<RuntimeOverridesOptions>()
+    .Bind(builder.Configuration.GetSection(RuntimeOverridesOptions.SectionName));
 
 // ---- Dnsmasq options (required paths validated at startup) ----
 builder.Services.AddOptions<DnsmasqOptions>()
@@ -30,9 +41,11 @@ builder.Services.AddDnsmasqApiHttpClients();
 
 builder.Services.AddControllers()
     .AddJsonOptions(o => ApiJsonOptions.ConfigureServer(o.JsonSerializerOptions));
+builder.Services.AddSignalR();
 builder.Services.AddRazorComponents()
     .AddInteractiveServerComponents();
 
+builder.Logging.AddAppLogs(builder.Configuration);
 builder.Services.AddCorsFromConfiguration(builder.Configuration);
 
 var app = builder.Build();
@@ -59,6 +72,7 @@ app.UseAntiforgery();
 
 // ---- Endpoints ----
 app.MapControllers();
+app.MapHub<LogsHub>("/hubs/logs");
 // UseStaticFiles: MapStaticAssets returns 0-byte responses for fingerprinted assets (known bug). Serve from wwwroot directly.
 app.UseStaticFiles();
 app.MapRazorComponents<App>()

src/DnsmasqWebUI/appsettings.json

@@ -5,9 +5,22 @@
   "Logging": {
     "LogLevel": {
       "Default": "Information",
-      "Microsoft.AspNetCore": "Warning"
+      "Microsoft.AspNetCore": "Warning",
+      "Microsoft.Hosting.Lifetime": "Information",
+      "System.Net.Http.HttpClient": "Warning"
     }
   },
+  "AppLogs": {
+    "ExcludedCategoryPrefixes": [
+      "Microsoft.AspNetCore.Components.",
+      "Microsoft.AspNetCore.Server.Kestrel.Transport.",
+      "Microsoft.AspNetCore.Server.Kestrel.Connections",
+      "System.Net.Http.",
+      "Microsoft.Extensions.Http.",
+      "Microsoft.AspNetCore.Hosting.",
+      "Microsoft.AspNetCore.Routing."
+    ]
+  },
   "AllowedHosts": "*",
   "ForwardedHeaders": {
     "Enabled": false

src/DnsmasqWebUI/wwwroot/js/logs.js

@@ -0,0 +1,37 @@
+/**
+ * Logs terminal: append/replace content with optional max lines and auto-scroll. Used by LogsSection for dnsmasq and app logs.
+ * @param {string} elementId - id of the pre element
+ * @param {string} content - log content to append or replace
+ * @param {{ maxLines?: number, autoScroll?: boolean }} [options] - maxLines: truncate to last N lines; autoScroll: scroll to bottom (default true)
+ */
+export function appendLogs(elementId, content, options = {}) {
+    const el = document.getElementById(elementId);
+    if (!el) return;
+    el.textContent += content;
+    truncateToMaxLines(el, options.maxLines);
+    if (options.autoScroll !== false)
+        scrollLogsToBottom(elementId);
+}
+
+export function replaceLogs(elementId, content, options = {}) {
+    const el = document.getElementById(elementId);
+    if (!el) return;
+    el.textContent = content;
+    truncateToMaxLines(el, options.maxLines);
+    if (options.autoScroll !== false)
+        scrollLogsToBottom(elementId);
+}
+
+function truncateToMaxLines(el, maxLines) {
+    if (maxLines == null || maxLines <= 0) return;
+    const text = el.textContent || '';
+    const lines = text.split('\n');
+    if (lines.length <= maxLines) return;
+    el.textContent = lines.slice(-maxLines).join('\n');
+}
+
+export function scrollLogsToBottom(elementId) {
+    const el = document.getElementById(elementId);
+    if (!el) return;
+    el.scrollTop = el.scrollHeight;
+}