Hi there!

I've got the following problem. I'm running FreeBSD 4.9 (PIII, 512Mb RAM),
Courier 0.45.5, Apache 1.3.31. I've also got Amavis-new running through Courier
filters, using ClamAv (+FreshClam) and SpamAssassin.

The problem is that all of sudden, some time ago the system ran into trouble.
Every several hours it gets flooded with the following processes (ps -aux):

courier 11425 0,0 0,0 1764 0 ?? IW - 0:00,00 submit esmtp dns;
justyna. www 11454 0,0 0,0 1728 0 ?? IW - 0:00,00 submit local dns;
localhos courier 11460 0,0 0,0 1748 0 ?? IW - 0:00,00 submit esmtp dns;
pD9E041E courier 11524 0,0 0,0 1744 0 ?? IW - 0:00,00 submit esmtp dns;
mail2.ez www 11532 0,0 0,0 1744 0 ?? IW - 0:00,00 submit local dns;
localhos courier 11611 0,0 0,0 1760 0 ?? IW - 0:00,00 submit esmtp dns;
69-167-7

Submits are owned by courier and apache. The number of those processes grows up
to hundreds and the mail system halts. I mean, it does work, IMAP and POP do
work, but mail doesn't deliver. Once I restart Apache and Courier (and those
submits are terminated), it gets back to work, all the mail is being delivered.
Till next flood.

What could that be? I'm getting frustrated with that and just have no idea what
to do. I was thinking about Amavis as a bottleneck in the system and tried to
turn off Spam filtering, but that didn't help. I'm not risking to turn of
ClamAv, or Amavis at all, but could that be a problem?

I was also doing some FreeBSD tuning lately (maxsockbuf, somaxconn, nmbclusters,
maxsockets, etc), but that was working fine for several weeks.

Thanks,