[TAG] DNS proxy/cache (Tip)

[Karl-Heinz Herrmann]

Hi,


I had an annoying little problem: My home network has grown to 3 PC's --
one directly on the phone line, the others connected via WLAN. Usually I
would pick one dial-up provider and stick with that. Unfortunately the
German ISP's are a big mess of call-by call providers with constantly
changing tarifs. 

The directly connected box is only the dial-in and firewall/NAT Router,
the other two are my Laptop and desktop. 

The annoying problem: Everytime I change the provider I had to change
the resolv.conf on all systems according to the new nameservers as
transmitted via [i]ppp protocol. 

My solution: dproxy
http://dproxy.sourceforge.net/

It serves as a proxy/cache for DNS lookups. It uses regular sys-calls
for namelookups and reacts instantly (no kill -HUP or similar) to new
entries in /etc/resolv.conf. This is on the router of course and
everytime pppd changes the resolv.conf for the new provider it simply
uses the new values. 

The other two machines have the router as the nameserver and always get
the correct information (even offline, so a connection is of course not
possible). No manual changing anymore.


K.-H.