[Dnsmasq-discuss] Return an address if unable to resolve?

[Simon Kelley]

Doug Moeller wrote:
> Thanks for the replys.  A couple of notes that might better define my 
> problem.
> 
> The clients that will be accessing this will be web only and 
> unfortunately I don't have the ability to change their configuration.
> 
> I have the redirect to port 80 in the system already,  but that doesn't 
> really solve my problem because the client will do a DNS lookup first 
> and if that fails it won't try to connect to the web server at all.  
> What I need is for the DNS lookup to return an address when the DNS 
> lookup fails so that I can redirect them to port 80 on the localhost.
> Thanks
> 
> -DOug
> 

I understand: is your enviroment one where you know that the network 
uplink is down, or is a DNS timeout the first sign of trouble?

This rather strange syntax:

address=/#/1.2.3.4

will _unconditionally_ return 1.2.3.4 for any A-record query which can't 
be answered from /etc/hosts or DHCP.

If you have a script which run on net up/down, you could re-congfigure 
dnsmasq using that (you'll need a restart, but that's very cheap): on 
net down do

kill -TERM `cat /var/run/dnsmasq.pid`
dnsmasq --address=/#/1.2.3.4

on net up do

kill -TERM `cat /var/run/dnsmasq.pid`
dnsmasq

If, on the other hand you loose network connectivity silently, the 
problem is rather more difficult.

Cheers,

Simon.