OK. Here's my issue. I will start at the beginning just in case these events are related. About 3 weeks ago, I was remotely connected to the PDC(NT 4.0)/Exchange 5.5 Server via VNC from my workstation in the office. I was in the middle of creating a user mailbox in Exchange Administrator, when I lost my connection. Others in the office were suddenly locked up at the same time. Upon examining the server, I noticed that it was powered off. It appeared to have shut itself down suddenly. After rebooting, & checking the services, I noticed that quite a few of the Exchange related services had not started on their own. Further examination showed that "Startup" on these services was now set to "Manual" instead of "Automatic". I've never seen settings such as these change on their own.
OK, so I get Exchange & its services back up & running & everything seems to be going well. However, the last two Fridays, incoming internet Email has stopped working. Outgoing still works & internet connectivity is still there (DSL connection). The server needs to be rebooted in order to put things right. I have yet to see anything in the event log that can clue me in to what is going on.
From the senders' end here is an exerpt of the non-deliverable report:
"xxx.xxx.xxx.xxx does not like recipient. Remote host said: 550 Unable to relay for firstname.lastname@example.org. Giving up on xxx.xxx.xxx.xxx." NAT is used on the Netopia Router with ports 110 & 25 open. Mail has been working just fine for ever up until just these last couple weeks.
I'm not even certain that the first event is related to the intermittent incoming mail outages. Just looking for some ideas on how to troubleshoot this one. It now seems to be happening daily.
Thanks in advance for your assistance.