Use ISA live monitoring and see what the logs show you. Also, grab NetMon 3 and get concurrent internal/external captures while you test. The answers lie within... From: isalist-bounce@xxxxxxxxxxxxx [mailto:isalist-bounce@xxxxxxxxxxxxx] On Behalf Of ISA Sent: Thursday, January 18, 2007 1:47 PM To: isalist@xxxxxxxxxxxxx Subject: [isalist] SMTP Connection Closed Hope someone can help! I think this is an ISA 2004 (patched) issue. From some clients I can send/receive email just fine (and telnet port 25). But from other clients I can not. I monitored the ISA logs and observed the connection initiated then being closed. From Exchange 2003 box I shut of IMF and GFI services - still not luck receiving email or telnet'ing from a particular client. Any ideas would be greatly appreciated. Respectfully Joseph Danielsen, MCSA-Messaging, MCP Network Blade Inc. 49 Marcy Street Somerset, NJ 0887 732-213-0600 All mail to and from this domain is GFI-scanned.