postmaster / resolv.conf / dns problem

I'm running 7.4.8 on RHEL 3.0 x86.

Today, on two separate servers, I modified the resolv.conf file to point
from two functioning name servers to two others.

Within 5 minutes, one server would not accept new remote connections. I
could log in fine w/ psql locally.

All name servers involved were working fine before, during, and after.

Postgres kept spawning additional postmaster processes, they'd run for a
few seconds/minutes, then die. There was nothing in the logs other than
routine queries / transaction log recycling.

I bounced postgres, and everything is fine.

45 minutes later, the second server did the exact same thing.

Anyone ever seen this?

thanks!