Tony Houghton wrote:
> SA used to kill a different router I used to have, but I don't think
> that's the problem here.

I don't see how even a low end router would have a problem with the
amount of data from DNS lookups that could be generated. It must have
been something else.

> I temporarily pointed /etc/resolv.conf to my ISP's servers and
> restarted spamd, which you'd expect to make at least some
> difference, but it didn't really. Besides, I can still freely browse
> the web etc while SA is stalled on these lookups.

You might want to try out one of the RBL check tools.

Basically 'rblcheck' and see how long that takes. It
is very similar to what SA would be doing internally. If that is slow
then you have a smaller problem to debug. If that is fast then SA's
dsn lookup is probably not your problem and you can look at other
things that might be running slowly.