DHCP: read-only hosts from other configs, combobox inputs, polling, UI fixes

- Static hosts: read dhcp-host from all config files; show external as read-only
  with Source column; IsEditable + SourcePath on DhcpHostEntry; reject save if
  managed entry duplicates MAC from another file (400 + message)
- Lease field: single input + datalist (type or select), remove Other dropdown
- MAC field: single input + datalist from current leases, TryFillFromLeaseByMac
- Add host: default Name=*, suggest next free IP from DHCP range
- Leases: configurable refresh polling; Settings modal for interval (client-side)
- DhcpHostsClient: surface 400 error body message on save failure
- App title config (ApplicationOptions), nav/layout/error/hosts tweaks

docker-compose.test.yml

@@ -1,4 +1,5 @@
-# Run the app with real dnsmasq and a DHCP client so hosts/leases are real.
+# Run the app with real dnsmasq and several DHCP clients so hosts/leases are real.
+# Some clients also make periodic DNS requests so the DNS cache and logs show activity.
 # Prepare mount: ./scripts/prepare-test-mount.sh [--prepare-only | --no-build | --recreate | --source DIR | --mount DIR]
 # Or set TESTDATA_MOUNT to override the data volume (default: ./testdata-mount).
 #
@@ -31,11 +32,58 @@ services:
     networks:
       testnet:
         ipv4_address: 172.28.0.2
-    # no depends_on: app is the only service the client needs
 
+  # DHCP only; keeps running with lease.
   dhcp-client:
     image: alpine:3.20
-    command: ["sh", "-c", "sleep 5 && udhcpc -i eth0 -f -n"]
+    command: ["sh", "-c", "sleep 5 && exec udhcpc -i eth0 -f -n"]
+    networks:
+      testnet: {}
+    depends_on:
+      - app
+
+  # DHCP + periodic DNS lookups (every 20s) so DNS cache/logs show activity.
+  dhcp-client-dns-a:
+    image: alpine:3.20
+    command:
+      - sh
+      - -c
+      - |
+        udhcpc -i eth0 -f -n &
+        sleep 10
+        while true; do
+          nslookup google.com 2>/dev/null || true
+          nslookup cloudflare.com 2>/dev/null || true
+          sleep 20
+        done
+    networks:
+      testnet: {}
+    depends_on:
+      - app
+
+  # DHCP + periodic DNS lookups (every 45s); different interval for variety.
+  dhcp-client-dns-b:
+    image: alpine:3.20
+    command:
+      - sh
+      - -c
+      - |
+        udhcpc -i eth0 -f -n &
+        sleep 10
+        while true; do
+          nslookup example.com 2>/dev/null || true
+          nslookup github.com 2>/dev/null || true
+          sleep 45
+        done
+    networks:
+      testnet: {}
+    depends_on:
+      - app
+
+  # Third DHCP-only client so the leases table has more entries.
+  dhcp-client-2:
+    image: alpine:3.20
+    command: ["sh", "-c", "sleep 8 && exec udhcpc -i eth0 -f -n"]
     networks:
       testnet: {}
     depends_on:

scripts/dnsmasq-status.sh

@@ -1,6 +1,6 @@
 #!/bin/sh
 # Simulates "systemctl status dnsmasq" output when run in a container without systemd.
-# Uses ps/pgrep. Memory is RSS; the time shown is process uptime (elapsed), not CPU usage.
+# Uses ps/pgrep. Memory is RSS. Uptime line omitted; Active line has break after semicolon with continuation indented.
 
 pid=$(pgrep -x dnsmasq)
 if [ -z "$pid" ]; then
@@ -49,10 +49,11 @@ function fmt_since(s,   n, a, mon_num, day_pad) {
   rss_mb = (rss+0) / 1024
   if (rss_mb < 0.1) rss_mb = 0.0
 
+  # Active line: break after semicolon; continuation (e.g. "4 min ago") on next line, indented to align after "Active: "
   if (lstart != "") {
     since = fmt_since(lstart)
     ago = etime_ago(etime)
-    active_line = "     Active: active (running) since " since "; " ago
+    active_line = "     Active: active (running) since " since ";\n             " ago
   } else {
     active_line = "     Active: active (running) since container start"
   }
@@ -62,7 +63,6 @@ function fmt_since(s,   n, a, mon_num, day_pad) {
   printf "%s\n", active_line
   printf "   Main PID: %s (dnsmasq)\n", pid
   printf "     Memory: %.1fM\n", rss_mb
-  printf "     Uptime: %s\n", etime
   printf "     CGroup: (container)\n"
   printf "             └─%s %s\n", pid, args
 }'

src/DnsmasqWebUI/Client/Http/DhcpHostsClient.cs

@@ -1,6 +1,7 @@
+using System.Net.Http.Json;
+using System.Text.Json.Serialization;
 using DnsmasqWebUI.Client.Http.Abstractions;
 using DnsmasqWebUI.Models;
-using System.Net.Http.Json;
 
 namespace DnsmasqWebUI.Client.Http;
 
@@ -19,8 +20,25 @@ public sealed class DhcpHostsClient : IDhcpHostsClient
     public async Task<SaveWithReloadResult> SaveDhcpHostsAsync(IReadOnlyList<DhcpHostEntry> entries, CancellationToken ct = default)
     {
         var response = await _http.PutAsJsonAsync("api/dhcp/hosts", entries, ct);
-        response.EnsureSuccessStatusCode();
+        if (!response.IsSuccessStatusCode)
+        {
+            var body = await response.Content.ReadAsStringAsync(ct);
+            var msg = response.ReasonPhrase ?? response.StatusCode.ToString();
+            if (!string.IsNullOrEmpty(body) && body.TrimStart().StartsWith("{"))
+            {
+                try
+                {
+                    var err = System.Text.Json.JsonSerializer.Deserialize<JsonError>(body);
+                    if (!string.IsNullOrEmpty(err?.Error))
+                        msg = err.Error;
+                }
+                catch { /* use msg as-is */ }
+            }
+            throw new HttpRequestException(msg);
+        }
         return await response.Content.ReadFromJsonAsync<SaveWithReloadResult>(ct)
             ?? throw new InvalidOperationException("Unexpected null from api/dhcp/hosts.");
     }
+
+    private sealed class JsonError { [JsonPropertyName("error")] public string? Error { get; set; } }
 }

src/DnsmasqWebUI/Client/Models/ClientSettings.cs

@@ -10,4 +10,7 @@ public class ClientSettings
 
     /// <summary>Polling interval for the recent logs block (seconds).</summary>
     public int RecentLogsPollingIntervalSeconds { get; set; } = 5;
+
+    /// <summary>Polling interval for the DHCP leases list (seconds).</summary>
+    public int LeasesPollingIntervalSeconds { get; set; } = 5;
 }

src/DnsmasqWebUI/Client/Models/SettingsModalContext.cs

@@ -12,5 +12,8 @@ public enum SettingsModalContext
     ServicePolling,
 
     /// <summary>Show only recent logs polling interval.</summary>
-    LogsPolling
+    LogsPolling,
+
+    /// <summary>Show only DHCP leases refresh interval.</summary>
+    LeasesPolling
 }

src/DnsmasqWebUI/Components/App.razor

@@ -1,3 +1,4 @@
+@inject IOptions<ApplicationOptions> AppOptions
 <!DOCTYPE html>
 <html lang="en">
 
@@ -11,7 +12,7 @@
     <link rel="stylesheet" href="@Assets["DnsmasqWebUI.styles.css"]" />
     <ImportMap />
     <link rel="icon" type="image/png" href="favicon.png" />
-    <title>Local DNS</title>
+    <title>@_appTitle</title>
     <HeadOutlet />
 </head>
 
@@ -21,3 +22,6 @@
 </body>
 
 </html>
+@code {
+    private string _appTitle => AppOptions!.Value!.EffectiveTitle;
+}

src/DnsmasqWebUI/Components/Layout/NavMenu.razor

@@ -1,10 +1,11 @@
 @namespace DnsmasqWebUI.Components.Layout
+@inject IOptions<ApplicationOptions> AppOptions
 
 <div class="top-row ps-3 navbar navbar-dark">
     <div class="container-fluid d-flex align-items-center">
-        <a class="navbar-brand d-flex align-items-center gap-2" href="" aria-label="Local DNS home">
+        <a class="navbar-brand d-flex align-items-center gap-2" href="" aria-label="@AppTitle home">
             <i class="bi bi-globe brand-icon" aria-hidden="true"></i>
-            <span>Local DNS</span>
+            <span>@AppTitle</span>
         </a>
     </div>
 </div>
@@ -31,3 +32,6 @@
     </nav>
 </div>
 
+@code {
+    private string AppTitle => AppOptions!.Value!.EffectiveTitle;
+}

src/DnsmasqWebUI/Components/Modals/SettingsModal.razor

@@ -38,6 +38,15 @@
                                @bind="_editingSettings.RecentLogsPollingIntervalSeconds" />
                     </section>
                 }
+                @if (ShouldShowSection("Leases"))
+                {
+                    <section class="mb-4">
+                        <h6 class="text-muted">DHCP leases</h6>
+                        <label for="leases-interval" class="form-label">Refresh interval (seconds)</label>
+                        <input id="leases-interval" type="number" class="form-control" min="5" step="1"
+                               @bind="_editingSettings.LeasesPollingIntervalSeconds" />
+                    </section>
+                }
             </div>
             <div class="modal-footer">
                 <button type="button" class="btn btn-secondary" @onclick="Close">Cancel</button>

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

@@ -42,7 +42,8 @@ public partial class SettingsModal : IAsyncDisposable
             _editingSettings = new ClientSettings
             {
                 ServiceStatusPollingIntervalSeconds = _editingSettings.ServiceStatusPollingIntervalSeconds,
-                RecentLogsPollingIntervalSeconds = _editingSettings.RecentLogsPollingIntervalSeconds
+                RecentLogsPollingIntervalSeconds = _editingSettings.RecentLogsPollingIntervalSeconds,
+                LeasesPollingIntervalSeconds = _editingSettings.LeasesPollingIntervalSeconds
             };
         }
     }
@@ -73,6 +74,8 @@ public partial class SettingsModal : IAsyncDisposable
             return key == "ServiceStatus";
         if (SettingsContext == SettingsModalContext.LogsPolling)
             return key == "Logs";
+        if (SettingsContext == SettingsModalContext.LeasesPolling)
+            return key == "Leases";
         if (SettingsContext == SettingsModalContext.All)
         {
             if (string.IsNullOrWhiteSpace(_searchTerm)) return true;
@@ -81,6 +84,7 @@ public partial class SettingsModal : IAsyncDisposable
             {
                 "ServiceStatus" => "service status polling".Contains(term, StringComparison.OrdinalIgnoreCase),
                 "Logs" => "recent logs polling".Contains(term, StringComparison.OrdinalIgnoreCase),
+                "Leases" => "dhcp leases refresh polling".Contains(term, StringComparison.OrdinalIgnoreCase),
                 _ => false
             };
         }
@@ -93,6 +97,8 @@ public partial class SettingsModal : IAsyncDisposable
             _editingSettings.ServiceStatusPollingIntervalSeconds, 5, 300);
         _editingSettings.RecentLogsPollingIntervalSeconds = Math.Clamp(
             _editingSettings.RecentLogsPollingIntervalSeconds, 5, 300);
+        _editingSettings.LeasesPollingIntervalSeconds = Math.Clamp(
+            _editingSettings.LeasesPollingIntervalSeconds, 5, 300);
 
         await ClientSettingsService.SaveSettingsAsync(_editingSettings);
         if (_jsModule != null)

src/DnsmasqWebUI/Components/Pages/Dhcp.razor

@@ -6,8 +6,11 @@
 @inject IDhcpHostsClient DhcpHostsClient
 @inject ILeasesClient LeasesClient
 @inject IReloadClient ReloadClient
+@inject IClientSettingsService ClientSettingsService
+@inject IOptions<ApplicationOptions> AppOptions
+@implements IDisposable
 
-<PageTitle>DHCP | Local DNS</PageTitle>
+<PageTitle>DHCP | @AppTitle</PageTitle>
 
 <h1 class="page-title">DHCP</h1>
 
@@ -29,6 +32,15 @@ else
         }
         else
         {
+    <p class="text-muted small mb-2">Managed file: @_status.ManagedFilePath</p>
+    <div class="row g-2 align-items-center mb-2">
+        <div class="col-auto">
+            <label for="filter-keyword" class="form-label mb-0 small text-muted">Search static hosts</label>
+        </div>
+        <div class="col-md-4 col-lg-3">
+            <input type="text" id="filter-keyword" class="form-control form-control-sm" placeholder="MAC, name, address, comment…" @bind="_filterKeyword" @bind:event="oninput" />
+        </div>
+    </div>
     @if (_status.DnsmasqStatus == "inactive" || _status.DnsmasqStatus == "unknown")
     {
         <div class="alert alert-warning">Dnsmasq service appears to be <strong>@_status.DnsmasqStatus</strong>. Save will update the file but reload may fail until the service is fixed.</div>
@@ -42,43 +54,188 @@ else
         <div class="alert alert-success">@_message</div>
     }
     <div class="table-responsive-cards">
-        <table class="table table-bordered">
-            <thead>
-                <tr>
-                    <th>#</th><th>Valid</th><th>MAC</th><th>Name</th><th>Address</th><th>Lease</th><th>Ignore</th><th>Comment</th><th></th>
-                </tr>
-            </thead>
-            <tbody>
-                @foreach (var e in _entries.Where(x => !x.IsDeleted))
-                {
-                    <tr class="@(e.IsComment ? "table-secondary" : "")" @key="e.Id">
-                        <td>@e.LineNumber</td>
-                        <td><input type="checkbox" checked="@(!e.IsComment)" @onchange="() => ToggleValid(e)" /></td>
-                        <td><input class="form-control form-control-sm" value="@string.Join(", ", e.MacAddresses)" @oninput="ev => SetMac(e, ev.Value?.ToString())" style="min-width:140px" /></td>
-                        <td><input class="form-control form-control-sm" @bind="e.Name" /></td>
-                        <td><input class="form-control form-control-sm" @bind="e.Address" style="min-width:100px" /></td>
-                        <td><input class="form-control form-control-sm" @bind="e.Lease" style="min-width:70px" /></td>
-                        <td><input type="checkbox" checked="@e.Ignore" @onchange="() => ToggleIgnore(e)" /></td>
-                        <td><input class="form-control form-control-sm" @bind="e.Comment" /></td>
-                        <td><button class="btn btn-sm btn-danger" @onclick="() => Delete(e)">Delete</button></td>
+        <div class="d-none d-md-block">
+            <table class="table table-bordered">
+                <thead>
+                    <tr>
+                        <th>#</th><th>Valid</th><th>MAC</th><th>Name</th><th>Address</th><th>Lease</th><th>Ignore</th><th>Comment</th><th>Source</th><th></th>
                     </tr>
-                }
-            </tbody>
-        </table>
+                </thead>
+                <tbody>
+                    @foreach (var e in _visibleStaticEntries)
+                    {
+                        var editable = IsEditable(e);
+                        <tr class="@(e.IsComment ? "table-secondary" : "") @(editable ? "" : "table-light")" @key="e.Id">
+                            <td>@e.LineNumber</td>
+                            @if (editable)
+                            {
+                                <td><input type="checkbox" checked="@(!e.IsComment)" @onchange="() => ToggleValid(e)" title="Uncheck to comment out this line in config (dnsmasq will ignore it)" /></td>
+                                <td>
+                                    <input class="form-control form-control-sm" list="static-host-lease-datalist" value="@string.Join(", ", e.MacAddresses)" @oninput="ev => OnMacInput(e, ev.Value?.ToString())" style="min-width:140px" placeholder="MAC or pick from leases" />
+                                    @if (_leases != null && _leases.Count > 0)
+                                    {
+                                        <datalist id="static-host-lease-datalist">
+                                            @foreach (var l in _visibleLeases)
+                                            {
+                                                <option value="@l.Mac">@l.Mac @(string.IsNullOrEmpty(l.Name) ? "" : $" – {l.Name}") @(string.IsNullOrEmpty(l.Address) ? "" : $" – {l.Address}")</option>
+                                            }
+                                        </datalist>
+                                    }
+                                </td>
+                                <td><input class="form-control form-control-sm" @bind="e.Name" placeholder="Name" /></td>
+                                <td><input class="form-control form-control-sm" @bind="e.Address" style="min-width:100px" placeholder="Address" /></td>
+                                <td>
+                                    <input class="form-control form-control-sm" list="lease-datalist" @bind="e.Lease" @bind:event="oninput" style="min-width:7rem" placeholder="e.g. infinite or seconds" />
+                                    <datalist id="lease-datalist">
+                                        @foreach (var p in LeaseDatalistOptions)
+                                        {
+                                            <option value="@p.Value">@p.Label</option>
+                                        }
+                                    </datalist>
+                                </td>
+                                <td><input type="checkbox" checked="@e.Ignore" @onchange="() => ToggleIgnore(e)" title="Add ignore flag so dnsmasq will not assign this client a lease" /></td>
+                                <td><input class="form-control form-control-sm" @bind="e.Comment" /></td>
+                                <td class="text-muted small">—</td>
+                                <td><button class="btn btn-sm btn-danger" @onclick="() => Delete(e)">Delete</button></td>
+                            }
+                            else
+                            {
+                                <td>@(e.IsComment ? "No" : "Yes")</td>
+                                <td>@string.Join(", ", e.MacAddresses)</td>
+                                <td>@e.Name</td>
+                                <td>@e.Address</td>
+                                <td>@e.Lease</td>
+                                <td>@(e.Ignore ? "Yes" : "No")</td>
+                                <td>@e.Comment</td>
+                                <td><span class="text-muted small" title="@e.SourcePath">@(e.IsEditable ? "—" : (string.IsNullOrEmpty(e.SourcePath) ? "" : System.IO.Path.GetFileName(e.SourcePath)))</span></td>
+                                <td></td>
+                            }
+                        </tr>
+                    }
+                </tbody>
+            </table>
+        </div>
+        <div class="d-md-none table-cards-mobile">
+            @foreach (var e in _visibleStaticEntries)
+            {
+                var editable = IsEditable(e);
+                <div class="card mb-2 @(e.IsComment ? "table-secondary" : "") @(editable ? "" : "border-start border-3 border-info")" @key="e.Id">
+                    <div class="card-body py-2">
+                        <div class="table-card-row"><span class="table-card-label">#</span> @e.LineNumber</div>
+                        @if (!string.IsNullOrEmpty(e.SourcePath))
+                        {
+                            <div class="table-card-row">
+                                <span class="table-card-label">Source</span>
+                                <span class="text-muted small" title="@e.SourcePath">@System.IO.Path.GetFileName(e.SourcePath)</span>
+                            </div>
+                        }
+                        <div class="table-card-row">
+                            <span class="table-card-label">Valid</span>
+                            <div class="table-card-control">
+                                @if (editable)
+                                {
+                                    <input type="checkbox" checked="@(!e.IsComment)" @onchange="() => ToggleValid(e)" title="Uncheck to comment out this line in config (dnsmasq will ignore it)" />
+                                }
+                                else
+                                {
+                                    <span>@(e.IsComment ? "No" : "Yes")</span>
+                                }
+                            </div>
+                        </div>
+                        <div class="table-card-row">
+                            <span class="table-card-label">MAC</span>
+                            @if (editable)
+                            {
+                                <div class="flex-grow-1" style="min-width:0">
+                                    <input class="form-control form-control-sm" list="static-host-lease-datalist-mobile" value="@string.Join(", ", e.MacAddresses)" @oninput="ev => OnMacInput(e, ev.Value?.ToString())" placeholder="MAC or pick from leases" style="min-width:0; width:100%" />
+                                    @if (_leases != null && _leases.Count > 0)
+                                    {
+                                        <datalist id="static-host-lease-datalist-mobile">
+                                            @foreach (var l in _visibleLeases)
+                                            {
+                                                <option value="@l.Mac">@l.Mac @(string.IsNullOrEmpty(l.Name) ? "" : $" – {l.Name}") @(string.IsNullOrEmpty(l.Address) ? "" : $" – {l.Address}")</option>
+                                            }
+                                        </datalist>
+                                    }
+                                </div>
+                            }
+                            else
+                            {
+                                <span>@string.Join(", ", e.MacAddresses)</span>
+                            }
+                        </div>
+                        <div class="table-card-row">
+                            <span class="table-card-label">Name</span>
+                            @if (editable) { <input class="form-control form-control-sm" @bind="e.Name" /> } else { <span>@e.Name</span> }
+                        </div>
+                        <div class="table-card-row">
+                            <span class="table-card-label">Address</span>
+                            @if (editable) { <input class="form-control form-control-sm" @bind="e.Address" /> } else { <span>@e.Address</span> }
+                        </div>
+                        <div class="table-card-row">
+                            <span class="table-card-label">Lease</span>
+                            @if (editable)
+                            {
+                                <input class="form-control form-control-sm" list="lease-datalist-mobile" @bind="e.Lease" @bind:event="oninput" style="min-width:0; width:100%" placeholder="e.g. infinite or seconds" />
+                                <datalist id="lease-datalist-mobile">
+                                    @foreach (var p in LeaseDatalistOptions)
+                                    {
+                                        <option value="@p.Value">@p.Label</option>
+                                    }
+                                </datalist>
+                            }
+                            else
+                            {
+                                <span>@e.Lease</span>
+                            }
+                        </div>
+                        <div class="table-card-row">
+                            <span class="table-card-label">Ignore</span>
+                            <div class="table-card-control">
+                                @if (editable) { <input type="checkbox" checked="@e.Ignore" @onchange="() => ToggleIgnore(e)" /> } else { <span>@(e.Ignore ? "Yes" : "No")</span> }
+                            </div>
+                        </div>
+                        <div class="table-card-row">
+                            <span class="table-card-label">Comment</span>
+                            @if (editable) { <input class="form-control form-control-sm" @bind="e.Comment" /> } else { <span>@e.Comment</span> }
+                        </div>
+                        @if (editable)
+                        {
+                            <div class="table-card-row mt-2">
+                                <button class="btn btn-sm btn-danger" @onclick="() => Delete(e)">Delete</button>
+                            </div>
+                        }
+                    </div>
+                </div>
+            }
+        </div>
+    </div>
+    <div class="d-flex flex-wrap align-items-center gap-2 mt-2">
+        <button class="btn btn-primary" @onclick="Add">Add host</button>
+        <button class="btn btn-primary" @onclick="Save" disabled="@_saving">Save</button>
+        @if (_status.ReloadCommandConfigured)
+        {
+            <button class="btn btn-primary" @onclick="Reload" disabled="@_saving">Reload config</button>
+        }
     </div>
-    <button class="btn btn-primary mt-2" @onclick="Add">Add host</button>
-    <button class="btn btn-primary mt-2" @onclick="Save" disabled="@_saving">Save</button>
-    @if (_status.ReloadCommandConfigured)
-    {
-        <button class="btn btn-primary mt-2" @onclick="Reload" disabled="@_saving">Reload config</button>
-    }
-    <p class="text-muted small mt-2">Managed file: @_status.ManagedFilePath</p>
         }
     </section>
 
     @* ---- Leases (dhcp-leasefile, read-only) ---- *@
     <section class="page-section">
-        <h2 class="page-section-title">Leases</h2>
+        <div class="d-flex align-items-center justify-content-between mb-2">
+            <h2 class="page-section-title mb-0">Leases</h2>
+            @if (_status.LeasesPathConfigured)
+            {
+                <button type="button" class="btn btn-link btn-sm p-0 text-body" aria-label="Leases refresh interval settings" @onclick="OpenLeasesSettings" title="Configure leases refresh interval">
+                    <i class="bi bi-gear-fill bi-gear-sm" aria-hidden="true"></i>
+                </button>
+            }
+        </div>
+        @if (_status.LeasesPathConfigured && !string.IsNullOrEmpty(_status.LeasesPath))
+        {
+            <p class="text-muted small mb-2">Path: @_status.LeasesPath (read-only).</p>
+        }
         @if (!_status.LeasesPathConfigured)
         {
             <p class="text-muted">Leases not configured (no dhcp-leasefile in config).</p>
@@ -94,45 +251,157 @@ else
         else if (_leases.Count == 0)
         {
             <p class="text-muted">No leases yet. Leases appear here when DHCP clients obtain an address; use Refresh to update.</p>
-            <p class="text-muted small">Path: @_status.LeasesPath</p>
-            <button class="btn btn-primary btn-sm mt-1" @onclick="LoadLeases" disabled="@_leasesLoading">Refresh</button>
+            <div class="d-flex flex-wrap align-items-center gap-2 mt-2">
+                <button class="btn btn-primary" @onclick="() => LoadLeases(showLoading: true)" disabled="@_leasesLoading">Refresh</button>
+            </div>
         }
         else
         {
+            <div class="row g-2 align-items-center mb-2">
+                <div class="col-auto">
+                    <label for="lease-filter-keyword" class="form-label mb-0 small text-muted">Search leases</label>
+                </div>
+                <div class="col-md-4 col-lg-3">
+                    <input type="text" id="lease-filter-keyword" class="form-control form-control-sm" placeholder="MAC, address, name, client ID…" @bind="_leaseFilterKeyword" @bind:event="oninput" />
+                </div>
+            </div>
             <div class="table-responsive-cards">
-                <table class="table table-bordered">
-                    <thead>
-                        <tr><th>Expiry</th><th>MAC</th><th>Address</th><th>Name</th><th>Client ID</th></tr>
-                    </thead>
-                    <tbody>
-                        @foreach (var e in _leases)
-                        {
-                            <tr>
-                                <td>@e.Timestamp.ToString("yyyy-MM-dd HH:mm:ss")</td>
-                                <td>@e.Mac</td>
-                                <td>@e.Address</td>
-                                <td>@e.Name</td>
-                                <td>@e.ClientId</td>
-                            </tr>
-                        }
-                    </tbody>
-                </table>
+                <div class="d-none d-md-block">
+                    <table class="table table-bordered">
+                        <thead>
+                            <tr><th>#</th><th>Expiry</th><th>MAC</th><th>Address</th><th>Name</th><th>Client ID</th><th>Control</th></tr>
+                        </thead>
+                        <tbody>
+                            @{ var leaseIndex = 0; }
+                            @foreach (var e in _visibleLeases)
+                            {
+                                var idx = ++leaseIndex;
+                                <tr>
+                                    <td>@idx</td>
+                                    <td>@e.Timestamp.ToString("yyyy-MM-dd HH:mm:ss")</td>
+                                    <td>@e.Mac</td>
+                                    <td>@e.Address</td>
+                                    <td>@e.Name</td>
+                                    <td>@e.ClientId</td>
+                                    <td>
+                                        <div class="d-flex flex-wrap gap-1">
+                                            <button type="button" class="btn btn-primary btn-sm" title="Add a new static host entry using this lease's MAC, name, and address" @onclick="() => AddStaticFromLease(e)">Add static</button>
+                                            <button type="button" class="btn btn-outline-danger btn-sm" title="Add a static host with ignore flag (dnsmasq will not assign this client a lease)" @onclick="() => AddStaticFromLeaseWithIgnore(e)">Ignore</button>
+                                        </div>
+                                    </td>
+                                </tr>
+                            }
+                        </tbody>
+                    </table>
+                </div>
+                <div class="d-md-none table-cards-mobile">
+                    @{ leaseIndex = 0; }
+                    @foreach (var e in _visibleLeases)
+                    {
+                        var idx = ++leaseIndex;
+                        <div class="card mb-2">
+                            <div class="card-body py-2">
+                                <div class="table-card-row"><span class="table-card-label">#</span> @idx</div>
+                                <div class="table-card-row"><span class="table-card-label">Expiry</span> @e.Timestamp.ToString("yyyy-MM-dd HH:mm:ss")</div>
+                                <div class="table-card-row"><span class="table-card-label">MAC</span> @e.Mac</div>
+                                <div class="table-card-row"><span class="table-card-label">Address</span> @e.Address</div>
+                                <div class="table-card-row"><span class="table-card-label">Name</span> @e.Name</div>
+                                <div class="table-card-row"><span class="table-card-label">Client ID</span> @e.ClientId</div>
+                                <div class="table-card-row mt-2 d-flex flex-wrap gap-1">
+                                    <button type="button" class="btn btn-primary btn-sm" title="Add a new static host entry using this lease's MAC, name, and address" @onclick="() => AddStaticFromLease(e)">Add static</button>
+                                    <button type="button" class="btn btn-outline-danger btn-sm" title="Add a static host with ignore flag (dnsmasq will not assign this client a lease)" @onclick="() => AddStaticFromLeaseWithIgnore(e)">Ignore</button>
+                                </div>
+                            </div>
+                        </div>
+                    }
+                </div>
+            </div>
+            <div class="d-flex flex-wrap align-items-center gap-2 mt-2">
+                <button class="btn btn-primary" @onclick="() => LoadLeases(showLoading: true)" disabled="@_leasesLoading">Refresh</button>
             </div>
-            <p class="text-muted small">Path: @_status.LeasesPath (read-only). Cached and refreshed when the file changes.</p>
-            <button class="btn btn-primary btn-sm mt-1" @onclick="LoadLeases" disabled="@_leasesLoading">Refresh</button>
         }
+        <SettingsModal IsVisible="_settingsModalOpen" Title="@_settingsModalTitle" SettingsContext="_settingsModalContext" OnClose="CloseSettingsModal" />
     </section>
 }
 
 @code {
+    private string AppTitle => AppOptions!.Value!.EffectiveTitle;
     private DnsmasqServiceStatus? _status;
     private List<DhcpHostEntry> _entries = new();
     private IReadOnlyList<LeaseEntry>? _leases;
+    private string _filterKeyword = "";
+    private string _leaseFilterKeyword = "";
     private bool _leasesLoading;
     private string? _error;
+    private Timer? _leasesRefreshTimer;
+    private int _leasesRefreshIntervalSeconds = 5;
     private string? _message;
+    private bool _settingsModalOpen;
+    private string _settingsModalTitle = "Client settings";
+    private SettingsModalContext _settingsModalContext = SettingsModalContext.All;
     private bool _saving;
 
+    private IEnumerable<DhcpHostEntry> _visibleStaticEntries =>
+        _entries.Where(x => !x.IsDeleted && StaticEntryMatchesKeyword(x, _filterKeyword));
+
+    private static bool IsEditable(DhcpHostEntry e) => e.IsEditable;
+
+    private static bool StaticEntryMatchesKeyword(DhcpHostEntry e, string keyword)
+    {
+        if (string.IsNullOrWhiteSpace(keyword)) return true;
+        var k = keyword.Trim();
+        var mac = string.Join(" ", e.MacAddresses);
+        return Contains(mac, k) || Contains(e.Name, k) || Contains(e.Address, k) || Contains(e.Lease, k) || Contains(e.Comment, k);
+    }
+
+    private static bool Contains(string? value, string keyword) =>
+        !string.IsNullOrEmpty(value) && value.Contains(keyword, StringComparison.OrdinalIgnoreCase);
+
+    private IEnumerable<LeaseEntry> _visibleLeases =>
+        _leases?.Where(e => LeaseEntryMatchesKeyword(e, _leaseFilterKeyword)) ?? Array.Empty<LeaseEntry>();
+
+    private static bool LeaseEntryMatchesKeyword(LeaseEntry e, string keyword)
+    {
+        if (string.IsNullOrWhiteSpace(keyword)) return true;
+        var k = keyword.Trim();
+        return Contains(e.Mac, k) || Contains(e.Address, k) || Contains(e.Name, k) || Contains(e.ClientId, k);
+    }
+
+    private static string LeaseKey(LeaseEntry e) => $"{e.Mac}|{e.Address}";
+
+    private void OnMacInput(DhcpHostEntry e, string? value)
+    {
+        SetMac(e, value);
+        TryFillFromLeaseByMac(e, value);
+    }
+
+    private void TryFillFromLeaseByMac(DhcpHostEntry e, string? value)
+    {
+        if (string.IsNullOrWhiteSpace(value) || _leases == null) return;
+        var mac = value.Trim();
+        if (mac.Contains(',')) return;
+        var lease = _visibleLeases.FirstOrDefault(l => string.Equals(l.Mac, mac, StringComparison.OrdinalIgnoreCase));
+        if (lease != null)
+        {
+            e.Name = lease.Name ?? "";
+            e.Address = lease.Address ?? "";
+            e.Lease = "infinite";
+        }
+        StateHasChanged();
+    }
+
+    private static readonly (string Value, string Label)[] LeaseDatalistOptions =
+    {
+        ("", "(none)"),
+        ("infinite", "Infinite"),
+        ("3600", "1 hour"),
+        ("21600", "6 hours"),
+        ("43200", "12 hours"),
+        ("86400", "24 hours"),
+        ("604800", "7 days"),
+        ("2592000", "30 days"),
+    };
+
     protected override async Task OnInitializedAsync()
     {
         await Load();
@@ -144,10 +413,14 @@ else
         _message = null;
         try
         {
+            var clientSettings = await ClientSettingsService.LoadSettingsAsync();
+            _leasesRefreshIntervalSeconds = Math.Clamp(clientSettings.LeasesPollingIntervalSeconds, 5, 300);
             _status = await StatusClient.GetStatusAsync();
             var entries = await DhcpHostsClient.GetDhcpHostsAsync();
             _entries = entries?.ToList() ?? new List<DhcpHostEntry>();
-            await LoadLeases();
+            await LoadLeases(showLoading: true);
+            if (_status != null && _status.LeasesPathConfigured && _leasesRefreshTimer == null)
+                StartLeasesRefreshTimer();
         }
         catch (Exception ex)
         {
@@ -155,10 +428,43 @@ else
         }
     }
 
-    private async Task LoadLeases()
+    private void OpenLeasesSettings()
+    {
+        _settingsModalContext = SettingsModalContext.LeasesPolling;
+        _settingsModalTitle = "Leases refresh interval";
+        _settingsModalOpen = true;
+    }
+
+    private async Task CloseSettingsModal()
+    {
+        _settingsModalOpen = false;
+        var clientSettings = await ClientSettingsService.LoadSettingsAsync();
+        _leasesRefreshIntervalSeconds = Math.Clamp(clientSettings.LeasesPollingIntervalSeconds, 5, 300);
+        if (_status != null && _status.LeasesPathConfigured)
+            StartLeasesRefreshTimer();
+    }
+
+    private void StartLeasesRefreshTimer()
+    {
+        _leasesRefreshTimer?.Dispose();
+        _leasesRefreshTimer = new Timer(
+            _ => _ = InvokeAsync(OnLeasesRefreshTick),
+            null,
+            TimeSpan.FromSeconds(_leasesRefreshIntervalSeconds),
+            TimeSpan.FromSeconds(_leasesRefreshIntervalSeconds));
+    }
+
+    private async Task OnLeasesRefreshTick()
     {
         if (_status == null || !_status.LeasesPathConfigured) return;
-        _leasesLoading = true;
+        await LoadLeases(showLoading: false);
+        await InvokeAsync(StateHasChanged);
+    }
+
+    private async Task LoadLeases(bool showLoading = true)
+    {
+        if (_status == null || !_status.LeasesPathConfigured) return;
+        if (showLoading) _leasesLoading = true;
         try
         {
             var resp = await LeasesClient.GetLeasesAsync();
@@ -166,16 +472,70 @@ else
         }
         finally
         {
-            _leasesLoading = false;
+            if (showLoading) _leasesLoading = false;
         }
     }
 
     private void Add()
     {
-        _entries.Add(new DhcpHostEntry { Id = "new:" + Guid.NewGuid().ToString("N"), LineNumber = 0, MacAddresses = new List<string>(), Extra = new List<string>() });
+        var nextAddress = GetNextAvailableAddress();
+        _entries.Add(new DhcpHostEntry
+        {
+            Id = "new:" + Guid.NewGuid().ToString("N"),
+            LineNumber = 0,
+            MacAddresses = new List<string>(),
+            Extra = new List<string>(),
+            Name = "*",
+            Address = nextAddress,
+            IsEditable = true
+        });
         StateHasChanged();
     }
 
+    private string? GetNextAvailableAddress()
+    {
+        if (_status == null || string.IsNullOrEmpty(_status.DhcpRangeStart) || string.IsNullOrEmpty(_status.DhcpRangeEnd))
+            return null;
+        if (!System.Net.IPAddress.TryParse(_status.DhcpRangeStart, out var startIp) || startIp.AddressFamily != System.Net.Sockets.AddressFamily.InterNetwork)
+            return null;
+        if (!System.Net.IPAddress.TryParse(_status.DhcpRangeEnd, out var endIp) || endIp.AddressFamily != System.Net.Sockets.AddressFamily.InterNetwork)
+            return null;
+        var used = new HashSet<uint>();
+        foreach (var e in _entries.Where(x => !x.IsDeleted && !string.IsNullOrEmpty(x.Address)))
+        {
+            if (System.Net.IPAddress.TryParse(e.Address, out var ip) && ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
+                used.Add(ToUint(ip));
+        }
+        if (_leases != null)
+        {
+            foreach (var l in _leases)
+            {
+                if (!string.IsNullOrEmpty(l.Address) && System.Net.IPAddress.TryParse(l.Address, out var ip) && ip.AddressFamily == System.Net.Sockets.AddressFamily.InterNetwork)
+                    used.Add(ToUint(ip));
+            }
+        }
+        var start = ToUint(startIp);
+        var end = ToUint(endIp);
+        if (start > end) return null;
+        for (var u = start; u <= end; u++)
+        {
+            if (!used.Contains(u))
+                return FromUint(u);
+        }
+        return null;
+    }
+
+    private static uint ToUint(System.Net.IPAddress ip)
+    {
+        var b = ip.GetAddressBytes();
+        return ((uint)b[0] << 24) | ((uint)b[1] << 16) | ((uint)b[2] << 8) | b[3];
+    }
+
+    private static string FromUint(uint u)
+    {
+        return $"{(u >> 24) & 0xff}.{(u >> 16) & 0xff}.{(u >> 8) & 0xff}.{u & 0xff}";
+    }
+
     private void Delete(DhcpHostEntry e)
     {
         e.IsDeleted = true;
@@ -200,6 +560,35 @@ else
         StateHasChanged();
     }
 
+    private void AddStaticFromLease(LeaseEntry lease)
+    {
+        AddStaticFromLeaseCore(lease, ignore: false);
+    }
+
+    private void AddStaticFromLeaseWithIgnore(LeaseEntry lease)
+    {
+        AddStaticFromLeaseCore(lease, ignore: true);
+    }
+
+    private void AddStaticFromLeaseCore(LeaseEntry lease, bool ignore)
+    {
+        _entries.Add(new DhcpHostEntry
+        {
+            Id = "new:" + Guid.NewGuid().ToString("N"),
+            LineNumber = 0,
+            IsComment = false,
+            IsDeleted = false,
+            Ignore = ignore,
+            MacAddresses = string.IsNullOrEmpty(lease.Mac) ? new List<string>() : new List<string> { lease.Mac },
+            Name = lease.Name ?? "",
+            Address = lease.Address ?? "",
+            Lease = "infinite",
+            Extra = new List<string>(),
+            Comment = null
+        });
+        StateHasChanged();
+    }
+
     private async Task Save()
     {
         _saving = true;
@@ -248,4 +637,10 @@ else
             _saving = false;
         }
     }
+
+    public void Dispose()
+    {
+        _leasesRefreshTimer?.Dispose();
+        _leasesRefreshTimer = null;
+    }
 }

src/DnsmasqWebUI/Components/Pages/Error.razor

@@ -1,8 +1,9 @@
 @page "/Error"
 @namespace DnsmasqWebUI.Components.Pages
 @using System.Diagnostics
+@inject IOptions<ApplicationOptions> AppOptions
 
-<PageTitle>Error | Local DNS</PageTitle>
+<PageTitle>Error | @AppTitle</PageTitle>
 
 <h1 class="page-title text-danger">Error</h1>
 <h2 class="text-danger">An error occurred while processing your request.</h2>
@@ -29,6 +30,7 @@
     [CascadingParameter]
     private HttpContext? HttpContext { get; set; }
 
+    private string AppTitle => AppOptions!.Value!.EffectiveTitle;
     private string? RequestId { get; set; }
     private bool ShowRequestId => !string.IsNullOrEmpty(RequestId);
 

src/DnsmasqWebUI/Components/Pages/Home.razor

@@ -5,9 +5,10 @@
 @inject IConfigSetClient ConfigSetClient
 @inject IReloadClient ReloadClient
 @inject IClientSettingsService ClientSettingsService
+@inject IOptions<ApplicationOptions> AppOptions
 @implements IDisposable
 
-<PageTitle>Overview | Local DNS</PageTitle>
+<PageTitle>Overview | @AppTitle</PageTitle>
 
 @if (_loading)
 {
@@ -156,6 +157,7 @@ else if (_status != null)
 }
 
 @code {
+    private string AppTitle => AppOptions!.Value!.EffectiveTitle;
     private int _serviceStatusIntervalSeconds = 15;
     private int _recentLogsIntervalSeconds = 15;
     private bool _settingsModalOpen;

src/DnsmasqWebUI/Components/Pages/Hosts.razor

@@ -3,8 +3,8 @@
 @namespace DnsmasqWebUI.Components.Pages
 @inject IStatusClient StatusClient
 @inject IHostsClient HostsClient
-
-<PageTitle>Hosts | Local DNS</PageTitle>
+@inject IOptions<ApplicationOptions> AppOptions
+<PageTitle>Hosts | @AppTitle</PageTitle>
 
 <h1 class="page-title">Hosts file</h1>
 
@@ -50,27 +50,42 @@ else
         <div class="alert alert-success">@_message</div>
     }
     <div class="table-responsive-cards">
-        <table class="table table-bordered">
-            <thead>
-                <tr><th>#</th><th>Address</th><th>Names</th></tr>
-            </thead>
-            <tbody>
-                @foreach (var e in _entries.Where(x => !x.IsPassthrough))
-                {
-                    <tr class="@(e.IsComment ? "table-secondary" : "")" @key="e.Id">
-                        <td>@e.LineNumber</td>
-                        <td>@e.Address</td>
-                        <td>@string.Join(", ", e.Names)</td>
-                    </tr>
-                }
-            </tbody>
-        </table>
+        <div class="d-none d-md-block">
+            <table class="table table-bordered">
+                <thead>
+                    <tr><th>#</th><th>Address</th><th>Names</th></tr>
+                </thead>
+                <tbody>
+                    @foreach (var e in _entries.Where(x => !x.IsPassthrough))
+                    {
+                        <tr class="@(e.IsComment ? "table-secondary" : "")" @key="e.Id">
+                            <td>@e.LineNumber</td>
+                            <td>@e.Address</td>
+                            <td>@string.Join(", ", e.Names)</td>
+                        </tr>
+                    }
+                </tbody>
+            </table>
+        </div>
+        <div class="d-md-none table-cards-mobile">
+            @foreach (var e in _entries.Where(x => !x.IsPassthrough))
+            {
+                <div class="card mb-2 @(e.IsComment ? "table-secondary" : "")" @key="e.Id">
+                    <div class="card-body py-2">
+                        <div class="table-card-row"><span class="table-card-label">#</span> @e.LineNumber</div>
+                        <div class="table-card-row"><span class="table-card-label">Address</span> @e.Address</div>
+                        <div class="table-card-row"><span class="table-card-label">Names</span> @string.Join(", ", e.Names)</div>
+                    </div>
+                </div>
+            }
+        </div>
     </div>
     <p class="text-muted small">Path: @_status.SystemHostsPath</p>
     <button class="btn btn-primary mt-2" @onclick="Save" disabled="@_saving">Save</button>
 }
 
 @code {
+    private string AppTitle => AppOptions!.Value!.EffectiveTitle;
     private DnsmasqServiceStatus? _status;
     private List<HostEntry> _entries = new();
     private string? _error;

src/DnsmasqWebUI/Components/_Imports.razor

@@ -13,5 +13,7 @@
 @using DnsmasqWebUI.Components.Modals
 @using DnsmasqWebUI.Components.Home
 @using DnsmasqWebUI.Models
+@using DnsmasqWebUI.Configuration
 @using DnsmasqWebUI.Client.Http.Abstractions
 @using DnsmasqWebUI.Services.Abstractions
+@using Microsoft.Extensions.Options

src/DnsmasqWebUI/Configuration/ApplicationOptions.cs

@@ -0,0 +1,20 @@
+namespace DnsmasqWebUI.Configuration;
+
+/// <summary>
+/// Application-level settings (title, etc.). Bound from "Application" config section
+/// (appsettings.json or Application__* environment variables).
+/// </summary>
+public class ApplicationOptions
+{
+    /// <summary>Configuration section name (e.g. "Application" for appsettings and Application__* env vars).</summary>
+    public const string SectionName = "Application";
+
+    /// <summary>Default application title when not configured.</summary>
+    public const string DefaultTitle = "Local DNS";
+
+    /// <summary>Application title shown in the navbar brand, page titles, and browser tab.</summary>
+    public string ApplicationTitle { get; set; } = DefaultTitle;
+
+    /// <summary>Title to use in UI (never null/empty).</summary>
+    public string EffectiveTitle => string.IsNullOrWhiteSpace(ApplicationTitle) ? DefaultTitle : ApplicationTitle;
+}

src/DnsmasqWebUI/Controllers/DhcpController.cs

@@ -42,6 +42,10 @@ public class DhcpController : ControllerBase
             var reload = await _reloadService.ReloadAsync(ct);
             return Ok(new SaveWithReloadResult(true, reload));
         }
+        catch (ArgumentException ex)
+        {
+            return BadRequest(new { error = ex.Message });
+        }
         catch (Exception ex)
         {
             return StatusCode(500, new { error = ex.Message });

src/DnsmasqWebUI/Controllers/StatusController.cs

@@ -32,6 +32,7 @@ public class StatusController : ControllerBase
             var set = await _configSetService.GetConfigSetAsync(ct);
             var effectiveLeasesPath = _configSetService.GetLeasesPath();
             var effectiveConfig = _configSetService.GetEffectiveConfig();
+            var (dhcpRangeStart, dhcpRangeEnd) = _configSetService.GetDhcpRange();
             var systemHostsPath = _options.SystemHostsPath?.Trim();
 
             var statusResult = await _processRunner.RunAsync(_options.StatusCommand, TimeSpan.FromSeconds(5), ct);
@@ -52,7 +53,7 @@ public class StatusController : ControllerBase
             var showResult = await showTask;
             var logsResult = await logsTask;
             var statusShowOutput = !string.IsNullOrWhiteSpace(_options.StatusShowCommand)
-                ? showResult.Stdout + (showResult.TimedOut ? "\n(Command timed out.)" : "")
+                ? FormatStatusShowOutput(showResult.Stdout + (showResult.TimedOut ? "\n(Command timed out.)" : ""))
                 : null;
             var logsOutput = !string.IsNullOrWhiteSpace(_options.LogsCommand)
                 ? logsResult.Stdout + (logsResult.TimedOut ? "\n(Command timed out.)" : "")
@@ -83,7 +84,9 @@ public class StatusController : ControllerBase
                 StatusCommandStdout: dnsmasqStatus != "active" ? statusCommandStdout : null,
                 StatusCommandStderr: dnsmasqStatus != "active" ? statusCommandStderr : null,
                 StatusShowOutput: statusShowOutput,
-                LogsOutput: logsOutput
+                LogsOutput: logsOutput,
+                DhcpRangeStart: dhcpRangeStart,
+                DhcpRangeEnd: dhcpRangeEnd
             );
             return Ok(status);
         }
@@ -93,6 +96,33 @@ public class StatusController : ControllerBase
         }
     }
 
+    /// <summary>
+    /// Reformats StatusShow output: Active line gets a line break after the semicolon;
+    /// continuation (e.g. "4 min ago") is indented to align with the value after "Active: ".
+    /// </summary>
+    private static string FormatStatusShowOutput(string raw)
+    {
+        if (string.IsNullOrWhiteSpace(raw)) return raw;
+        var lines = raw.Split('\n');
+        for (var i = 0; i < lines.Length; i++)
+        {
+            var line = lines[i];
+            var activeIdx = line.IndexOf("Active:", StringComparison.Ordinal);
+            if (activeIdx < 0) continue;
+            var semiIdx = line.IndexOf(';', activeIdx);
+            if (semiIdx < 0) continue;
+            var afterSemi = semiIdx + 1;
+            while (afterSemi < line.Length && line[afterSemi] == ' ') afterSemi++;
+            var continuation = afterSemi < line.Length ? line[afterSemi..].TrimEnd() : "";
+            var indentLength = activeIdx + "Active: ".Length;
+            var indent = new string(' ', indentLength);
+            lines[i] = continuation.Length > 0
+                ? line[..(semiIdx + 1)] + "\n" + indent + continuation
+                : line[..(semiIdx + 1)];
+        }
+        return string.Join("\n", lines);
+    }
+
     /// <summary>Returns the full log file from the path in effective config (log-facility). Untruncated.</summary>
     [HttpGet("logs/download")]
     public async Task<IActionResult> GetLogsDownload(CancellationToken ct)

src/DnsmasqWebUI/Models/DhcpHostEntry.cs

@@ -17,4 +17,10 @@ public class DhcpHostEntry
     public string? Lease { get; set; }
     public List<string> Extra { get; set; } = new();
     public string? Comment { get; set; }
+
+    /// <summary>True when this entry is from the managed file (editable). False when from main config or another file (read-only). Set by server on GET; new entries created in the UI should set this to true.</summary>
+    public bool IsEditable { get; set; }
+
+    /// <summary>Path to the config file this entry comes from. Set by server on GET; null for new entries not yet saved.</summary>
+    public string? SourcePath { get; set; }
 }

src/DnsmasqWebUI/Models/DnsmasqServiceStatus.cs

@@ -29,6 +29,8 @@ namespace DnsmasqWebUI.Models;
 /// <param name="StatusCommandStderr">Stderr of StatusCommand when dnsmasq is not active. Null when active or not configured.</param>
 /// <param name="StatusShowOutput">Output of StatusShowCommand (full service status). Null when not configured or command produced no output.</param>
 /// <param name="LogsOutput">Output of LogsCommand (recent logs preview). Null when not configured or command produced no output.</param>
+/// <param name="DhcpRangeStart">Start IP of the first dhcp-range= (e.g. 172.28.0.10). Null when not set or unparseable.</param>
+/// <param name="DhcpRangeEnd">End IP of the first dhcp-range= (e.g. 172.28.0.50). Null when not set or unparseable.</param>
 public record DnsmasqServiceStatus(
     string? SystemHostsPath,
     bool SystemHostsPathExists,
@@ -54,5 +56,7 @@ public record DnsmasqServiceStatus(
     string? StatusCommandStdout,
     string? StatusCommandStderr,
     string? StatusShowOutput,
-    string? LogsOutput
+    string? LogsOutput,
+    string? DhcpRangeStart,
+    string? DhcpRangeEnd
 );

src/DnsmasqWebUI/Program.cs

@@ -5,6 +5,10 @@ using Microsoft.Extensions.Options;
 
 var builder = WebApplication.CreateBuilder(args);
 
+// ---- Application options (title, etc.) ----
+builder.Services.AddOptions<ApplicationOptions>()
+    .Bind(builder.Configuration.GetSection(ApplicationOptions.SectionName));
+
 // ---- Dnsmasq options (required paths validated at startup) ----
 builder.Services.AddOptions<DnsmasqOptions>()
     .Bind(builder.Configuration.GetSection(DnsmasqOptions.SectionName))

src/DnsmasqWebUI/Services/Abstractions/IDnsmasqConfigSetService.cs

@@ -15,4 +15,7 @@ public interface IDnsmasqConfigSetService : IApplicationSingleton
 
     /// <summary>Additional hosts paths discovered from the config set (addn-hosts=; cumulative, all in order). Empty if none.</summary>
     IReadOnlyList<string> GetAddnHostsPaths();
+
+    /// <summary>Start and end IP of the last dhcp-range= (e.g. 172.28.0.10,172.28.0.50). Parsed from the raw value; (null, null) when not set or unparseable.</summary>
+    (string? Start, string? End) GetDhcpRange();
 }

src/DnsmasqWebUI/Services/DnsmasqConfigService.cs

@@ -29,22 +29,29 @@ public class DnsmasqConfigService : IDnsmasqConfigService
 
     public async Task<IReadOnlyList<DhcpHostEntry>> ReadDhcpHostsAsync(CancellationToken ct = default)
     {
-        var path = await GetManagedFilePathAsync(ct);
-        if (string.IsNullOrEmpty(path))
+        var set = await _configSetService.GetConfigSetAsync(ct);
+        if (string.IsNullOrEmpty(set.ManagedFilePath))
         {
             _logger.LogDebug("No managed file path (no conf-dir in main config); returning empty dhcp hosts");
             return Array.Empty<DhcpHostEntry>();
         }
-        if (!File.Exists(path))
+        var allEntries = new List<DhcpHostEntry>();
+        foreach (var file in set.Files)
         {
-            _logger.LogWarning("Managed config file not found: {Path}", path);
-            return Array.Empty<DhcpHostEntry>();
+            if (!File.Exists(file.Path))
+                continue;
+            var lines = await File.ReadAllLinesAsync(file.Path, Encoding.UTF8, ct);
+            var configLines = DnsmasqConfFileLineParser.ParseFile(lines);
+            var entries = configLines.OfType<DhcpHostLine>().Select(c => c.DhcpHost).ToList();
+            foreach (var e in entries)
+            {
+                e.SourcePath = file.Path;
+                e.IsEditable = file.IsManaged;
+            }
+            allEntries.AddRange(entries);
         }
-        var lines = await File.ReadAllLinesAsync(path, Encoding.UTF8, ct);
-        var configLines = DnsmasqConfFileLineParser.ParseFile(lines);
-        var entries = configLines.OfType<DhcpHostLine>().Select(c => c.DhcpHost).ToList();
-        AssignStableIds(entries);
-        return entries;
+        AssignStableIds(allEntries);
+        return allEntries;
     }
 
     /// <summary>Assign stable Ids so we can match by Id on write (reorder-safe). Content-based; ":LineNumber" appended for uniqueness when needed.</summary>
@@ -84,10 +91,23 @@ public class DnsmasqConfigService : IDnsmasqConfigService
 
     public async Task WriteDhcpHostsAsync(IReadOnlyList<DhcpHostEntry> entries, CancellationToken ct = default)
     {
-        var path = await GetManagedFilePathAsync(ct);
+        var set = await _configSetService.GetConfigSetAsync(ct);
+        var path = set.ManagedFilePath;
         if (string.IsNullOrEmpty(path))
             throw new InvalidOperationException("No managed file path (main config has no conf-dir). Cannot write dhcp hosts.");
 
+        var managedEntries = entries.Where(e => e.IsEditable).ToList();
+        var externalMacs = await GetMacsFromNonManagedFilesAsync(set, ct);
+        foreach (var e in managedEntries.Where(e => !e.IsDeleted))
+        {
+            foreach (var mac in e.MacAddresses.Where(m => !string.IsNullOrWhiteSpace(m)))
+            {
+                var normalized = mac.Trim();
+                if (externalMacs.TryGetValue(normalized, out var sourcePath))
+                    throw new ArgumentException($"MAC {mac} is already defined in {sourcePath}. Remove it from that file or use a different MAC.");
+            }
+        }
+
         var dir = Path.GetDirectoryName(path);
         if (!string.IsNullOrEmpty(dir) && !Directory.Exists(dir))
             Directory.CreateDirectory(dir);
@@ -103,7 +123,7 @@ public class DnsmasqConfigService : IDnsmasqConfigService
         var fileEntries = configLines.OfType<DhcpHostLine>().Select(c => c.DhcpHost).ToList();
         AssignStableIds(fileEntries);
 
-        var byId = entries.Where(e => !string.IsNullOrEmpty(e.Id)).GroupBy(e => e.Id, StringComparer.Ordinal).ToDictionary(g => g.Key, g => g.First(), StringComparer.Ordinal);
+        var byId = managedEntries.Where(e => !string.IsNullOrEmpty(e.Id)).GroupBy(e => e.Id, StringComparer.Ordinal).ToDictionary(g => g.Key, g => g.First(), StringComparer.Ordinal);
         var matchedIds = new HashSet<string>(StringComparer.Ordinal);
 
         for (var i = 0; i < configLines.Count; i++)
@@ -114,7 +134,7 @@ public class DnsmasqConfigService : IDnsmasqConfigService
             configLines[i] = new DhcpHostLine { LineNumber = dhcpLine.LineNumber, DhcpHost = replacement };
         }
 
-        var appended = entries.Where(e => (string.IsNullOrEmpty(e.Id) || !matchedIds.Contains(e.Id)) && !e.IsDeleted).ToList();
+        var appended = managedEntries.Where(e => (string.IsNullOrEmpty(e.Id) || !matchedIds.Contains(e.Id)) && !e.IsDeleted).ToList();
         var output = configLines.Select(DnsmasqConfFileLineParser.ToLine).ToList();
         foreach (var entry in appended)
             output.Add(DnsmasqConfDhcpHostLineParser.ToLine(entry));
@@ -125,6 +145,29 @@ public class DnsmasqConfigService : IDnsmasqConfigService
         _logger.LogInformation("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>
+    private static async Task<Dictionary<string, string>> GetMacsFromNonManagedFilesAsync(DnsmasqConfigSet set, CancellationToken ct)
+    {
+        var result = new Dictionary<string, string>(StringComparer.OrdinalIgnoreCase);
+        var managedPath = set.ManagedFilePath ?? "";
+        foreach (var file in set.Files.Where(f => !f.IsManaged && !string.Equals(f.Path, managedPath, StringComparison.Ordinal)))
+        {
+            if (!File.Exists(file.Path)) continue;
+            var lines = await File.ReadAllLinesAsync(file.Path, Encoding.UTF8, ct);
+            var configLines = DnsmasqConfFileLineParser.ParseFile(lines);
+            foreach (var dhcp in configLines.OfType<DhcpHostLine>().Select(c => c.DhcpHost))
+            {
+                foreach (var mac in dhcp.MacAddresses.Where(m => !string.IsNullOrWhiteSpace(m)))
+                {
+                    var normalized = mac.Trim();
+                    if (normalized.Length > 0 && !result.ContainsKey(normalized))
+                        result[normalized] = file.Path;
+                }
+            }
+        }
+        return result;
+    }
+
     public async Task<ManagedConfigContent> ReadManagedConfigAsync(CancellationToken ct = default)
     {
         var path = await GetManagedFilePathAsync(ct);

src/DnsmasqWebUI/Services/DnsmasqConfigSetService.cs

@@ -120,6 +120,36 @@ public class DnsmasqConfigSetService : IDnsmasqConfigSetService
         return GetEffectiveConfig().AddnHostsPaths;
     }
 
+    /// <inheritdoc />
+    public (string? Start, string? End) GetDhcpRange()
+    {
+        var set = GetConfigSet();
+        if (set.Files.Count == 0)
+            return (null, null);
+        var paths = set.Files.Select(f => f.Path).ToList();
+        var (raw, _) = DnsmasqConfIncludeParser.GetLastValueFromConfigFiles(paths, "dhcp-range");
+        return ParseDhcpRangeStartEnd(raw);
+    }
+
+    /// <summary>Parses dhcp-range value to (startIp, endIp). Format is typically start,end,mask,lease or tag:...,start,end,...; finds first two IPv4-looking tokens.</summary>
+    internal static (string? Start, string? End) ParseDhcpRangeStartEnd(string? raw)
+    {
+        if (string.IsNullOrWhiteSpace(raw)) return (null, null);
+        var parts = raw.Split(',');
+        string? start = null;
+        string? end = null;
+        foreach (var p in parts)
+        {
+            var t = p.Trim();
+            if (string.IsNullOrEmpty(t)) continue;
+            if (!System.Net.IPAddress.TryParse(t, out var ip) || ip.AddressFamily != System.Net.Sockets.AddressFamily.InterNetwork)
+                continue;
+            if (start == null) { start = t; continue; }
+            if (end == null) { end = t; break; }
+        }
+        return (start, end);
+    }
+
     private DnsmasqConfigSet GetConfigSet()
     {
         var mainPath = _options.MainConfigPath;

src/DnsmasqWebUI/appsettings.json

@@ -1,4 +1,7 @@
 {
+  "Application": {
+    "ApplicationTitle": "Local DNS"
+  },
   "Logging": {
     "LogLevel": {
       "Default": "Information",

src/DnsmasqWebUI/wwwroot/app.css

@@ -162,11 +162,49 @@ h1:focus {
     overflow-wrap: break-word;
 }
 
+/* Table: desktop shows table, mobile shows card list (via d-none d-md-block / d-md-none in markup) */
 .table-responsive-cards {
     overflow-x: auto;
     -webkit-overflow-scrolling: touch;
 }
 
+.table-responsive-cards .d-none.d-md-block {
+    overflow-x: auto;
+    -webkit-overflow-scrolling: touch;
+}
+
+.table-cards-mobile .card .table-card-row {
+    display: flex;
+    flex-wrap: wrap;
+    gap: 0.35rem 0.75rem;
+    align-items: baseline;
+    font-size: 0.9375rem;
+}
+
+.table-cards-mobile .card .table-card-row + .table-card-row {
+    margin-top: 0.25rem;
+}
+
+.table-card-label {
+    font-size: 0.8125rem;
+    color: var(--bs-secondary);
+    min-width: 4.5rem;
+    flex-shrink: 0;
+}
+
+.table-cards-mobile .table-card-row .form-control,
+.table-cards-mobile .table-card-row .form-select,
+.table-cards-mobile .table-card-row .table-card-control {
+    flex: 1;
+    min-width: 0;
+}
+
+/* Align checkboxes with other inputs in card mode: control starts at same column */
+.table-cards-mobile .table-card-row .table-card-control {
+    display: flex;
+    align-items: center;
+}
+
 /* Settings gear icon size (Bootstrap Icons) */
 .bi-gear-sm {
     font-size: 1.125rem;

src/DnsmasqWebUI/wwwroot/js/settings-modal.js

@@ -7,7 +7,8 @@
 export function initDialog(dialogElement, dotNetRef) {
   if (!dialogElement) return;
   dialogElement.addEventListener('close', function handler() {
-    dotNetRef.invokeMethodAsync('OnDialogClosed', dialogElement.returnValue ?? '');
+    // Ignore errors on page refresh/unload when the Blazor circuit is already gone
+    dotNetRef.invokeMethodAsync('OnDialogClosed', dialogElement.returnValue ?? '').catch(() => {});
   });
 }