Have a Dell Poweredge running SBS2003.
Sometimes, I can connect remotely using telnet on port 25 and ehlo the server.
Other times, I get no answer.
Once connected, everything seems to work well and at a good speed.
If I terminate from the server end, I can't reconnect for about 5 minutes.
If I disconnect from the client end, I can't reconnect for about 5 minutes, and the smtp sessions window continues to show me as logged in (yes... I hit refresh and yes... the seconds increment).
The problem?? We installed a Barracuda Spam Firewall. Works great until it doesn't have any email to forward for awhile. It times out (which is good). But then can't reconnect when it has more mail to forward to the server.