I have a client with an HP ML350 G4. Recently it has developed an issue where the network card will drop the connection for a split second, but long enough that it will often kick people out of this software they use that uses a SQL server. It happens about 4 times in an hour, usually about two hours out of the day. The rest of the time the connection is completely stable. For example today, from 11-12pm it disconnected and reconnected 4 times, then from 2-3pm it did it again. There is no consistancy in the times, it's different every day. The way we know it is disconnecting is the network card logs connects and disconnects in the system log. So it is essentially the same as someone very quickly unplugging the network cable and plugging it back in.
So far we have done the following: replaced the ethernet cable to the server, replaced the built in NIC with a PCI based NIC, and finally we replaced the clients main switch. After replacing each item we would wait to see if it failed before replacing the next item. I am now at the point where all parts that connect the server to the network have been replaced and the issue is still happening.
So anyone have any ideas on what could cause this? Were running Windows server 2003 standard set up as a domain controller, there is a sql server running, and the server hosts files, that's all it does.