It depends on your ISP. I was testing at one client site that had
access via a cable modem and we discovered that the ISP was resetting
our external IP every 15 minutes.

Matt Harting wrote:
Well, I just tried it, and found that the external IP address hasn't
changed, despite my SSH session being reset twice.

This is actually proving quite hard to troubleshoot.

Thanks for the idea
Michael Nelson

"Michael Nelson" wrote
office, or load up another server to test first in the place of this one, and later at
said other dsl place. That will confirm the trouble as centered on your dsl gear
versus the server configuration. You are lucky in a way, since the problem is so
bad that testing of ideas will proceed quickly.