-r, --resolv-file=<file>
Read the IP addresses of the upstream nameservers from <file>, instead of
/etc/resolv.conf. For the format of this file see
resolv.conf(5).
The only lines relevant to dnsmasq are nameserver ones. Dnsmasq can
be told to poll more than one resolv.conf file, the first file name specified
overrides the default, subsequent ones add to the list. This is only
allowed when polling; the file with the currently latest modification
time is the one used.