[ale] Cacheing-only nameserver on router

[Brian Pitts]

On 06/04/2010 11:44 AM, Ken Cochran wrote:
> Hey folks, any pointers (info, articles, links, docs) on how
> to "do" a caching-only nameserver on a router box?  OpenWRT?
> DD-Wrt?  Tomato?  I know how to do that on a "regular" Linux/BSD
> system but what I've used for that over the years is (hopefully
> only temporarily) down.  Umm, is there a router image that'll
> turn the thing into a system I can ssh into and configure/manage
> as I would a "real" machine (from the command-line)?  Sorta a
> "corollary:" Will a cache-only nameserver work if that system is
> on the "inside" LAN&  not the router/gateway box?  Thanks, -kc

If your ideal management interface is a shell, Openwrt will probably fit 
your style better than the others you mention. The documentation [0] 
isn't great, but for the most part once you have the current version of 
OpenWRT (8.09, commonly called 'kamikaze') installed have you can 
configure it like any linux system.

It will include dnsmasq [1], but you will be able to use opkg (think 
apt-get or yum) to install an alternate nameserver.  I don't see a 
compelling reason to switch; by default dnsmasq will be providing DHCP 
and DNS services, but it is straightforward to configure it to be only a 
DNS server.

There's no reason having a nameserver that isn't your gateway won't 
work. Make sure that the router running OpenWRT is configured to use a 
recursive nameserver. Dnsmasq will then forward queries to it. If you 
have another server providing DHCP services, configure it to hand out 
the IP address of your router running OpenWRT as the nameserver. If 
you're using static IP addresses, put the IP address of your router 
running OpenWRT in /etc/resolv.conf.

[0] http://kamikaze.openwrt.org/docs/openwrt.html
[1] http://thekelleys.org.uk/dnsmasq/doc

-- 
All the best,
Brian Pitts