[dns-operations] BIND forwarders question

[Tom Daly]

> My idea is to use forward X; on site Y and forward Y; on site X, but,
> as 
> I couldn't find it in the documents, I believe this could lead to a 
> resolver loop between X and Y and therefore even slower resolution. 
> Or is BIND clever enough to only ask the other server once?
> 
> The other option would be to only setup one site to forward to the 
> other, but that would only fill one cache good and the other poorer. 
> Still, as they resolve similar hosts, if the first option 
> can't/shouldn't be done, it's better than nothing.

I'm not quite sure I understand your question, but it sounds like your goal is to keep your caches as hot as possible. One way to do this is to instrument each server in a way that captures cache misses, and replicates the query to the other cache - forcing it to get its cache populated.

tcpdump + shell + ssh can do this for you.

Tom