[Dnsmasq-discuss] domain suffix and dns caching

[Simon Kelley]

Louis-Michel Gelinas wrote:
> Hi list,
>         
> I am using dnsmasq as a caching dns server, no DHCP. 
>         
> /etc/resolv.conf contains only : 
> nameserver 127.0.0.1
>         
> dnsmsq.conf contains:
>         
> resolv-file=/etc/resolv.conf.dnsmasq
> listen-address=127.0.0.1
> 
> and /etc/resolv.conf.dnsmasq is maintained by helper scripts. 
> 
> all is good and works fine, apart the domain suffix. 
> 
> I would like dnsmasq to ADD the suffix to queries without one. This is
> the job of libresolv if I understand correctly, and /etc/resolv.conf is
> only read once ( res_init will have it-reread, but I would like to find
> another solution, hence dnsmasq). 
> 
> The reason I use dnsmasq is to be able to change dns configs without
> restarting deamons (or using res_init). This works for dns servers, but
> changing the suffix does not. 
> 

Are you interested in local queries (stuff answered from /etc/hosts) or 
stuff passed upstream? There are some facilities to do the opposite of 
what you want: adding a suffix to un-decorated names in /etc/hosts, but 
not upstream queries.


> Can this be done with stock dnsmasq? Is my idea broken in the first
> place ? 
> 

I guess it depends on what you are doing: if you can arrange for the 
imap sever to be called mail.<domain> everywhere then there are some 
advantages, but you'll probably have to restart your mail client anyway.

> If this cannot be done with dnsmasq, is a patch welcome? any
> recommendations as to how to do this? 

It's much more difficult than you might at first think, because of the 
architecure of dnsmasq. A general solution (a search list of suffices to 
check in order) is pretty much impossible. Adding a single suffix to 
bare names is possible, but will need some new packet-manipulation code.

Cheers,

Simon.


> 
> Thanks
> Louis-Michel Gelinas
> 
>         
>         
>         
> 
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