resolv.conf - what generates it?

[Aaron Maxwell <amaxwell@phy.ucsf.edu>]

What tool generates /etc/resolv.conf, and how do I change what it
generates?

I'm running today's potato.  I need to change the contents of
/etc/resolv.conf (to change the nameserver line, and add a domain line
and a second nameserver line).  I can do this with vi no problem, but
it's temporary:  during reboot, and every few hours while the system
is up, something clobbers the new resolv.conf with the old one.  

Thanks in advance.  Aaron

The resolv.conf(5) manpage doesn't seem to help - when I get a correct
answer I'll file that as a bug report.