[Dnsmasq-discuss] dnsmasq for road warriors

[/dev/rob0]

Seems to me that dnsmasq is a better nscd replacement, and it has a
place in mobile computing.

# we use this dnsmasq as this system's own resolver
no-resolv
# I'm not sure if both of these are needed; we only want DNS and
# only on loopback; we serve only this machine.
no-dhcp-interface=lo
listen-address=127.0.0.1
user=dnsmasq
group=dnsmasq
# When connected to VPN, these names/addresses resolve. When not
# connected, they don't, but that's okay, because we can't get to
# them anyway.
server=/rob0.vpn/192.168.6.1
server=/6.168.192.in-addr.arpa/192.168.6.1
# upstream: Google Public DNS
server=8.8.4.4

The problem here is when you might not want to use 8.8.4.4, such as
when you're at a dnsmasq site where internal DNS is working. The 
solution, I guess, would be a hook in the DHCP client to write the 
DHCP-obtained nameserver[s] to a dnsmasq.d/file to include, and
signal or restart dnsmasq.

Problem with that solution: will dnsmasq.d get crufty, or do we just 
reuse the same file? Also, what if one of the mobile connections is 
not handled by DHCP, such as some cellular data connections?

Speaking of cruft, maybe that's not a bad thing? What will dnsmasq do 
with multiple upstream servers?

server=192.168.40.1
server=192.168.0.1
server=192.168.1.1
server=8.8.4.4

When we're at a site where one of those is our router, that should 
respond much faster than 8.8.4.4 can. OTOH, it could cause 
intermittent errors with local names; 8.8.4.4 is not going to know 
"minipax.rob0.lan".

Can we priortise upstream servers? --all-servers implies that this 
can be done somehow, but I don't know how ... is it merely the order 
in which they are listed in the config (or on the command line)? When 
not using --all-servers, how does dnsmasq decide when to try a 
different one, and which one will be tried in that case? Random 
selection, rotating sequential, fixed top-down priority?

Ideally we'd want something which you set up one time and is mostly 
done; something that should work at regular sites you frequent, as 
well as most public hotspots.
--
  http://rob0.nodns4.us/ -- system administration and consulting
  Offlist GMX mail is seen only if "/dev/rob0" is in the Subject: