It continues! As mentioned previously, I've followed the "Virtual Users And Domains With Postfix, Courier And MySQL (Fedora Core 5)" tutorial. Authentication, both plain and SSL, work fine for pop and smtp connections from within my 3 IP address block. Outside of my block, I can still receive mail with pop, but smtp hangs and doesn't send. There is no trace of an SMTP connection in /var/log/maillog in these cases. As long as I send from a system within my address block, it shows up as expected. This would suggest a firewall issue, but: Code: [[email protected] The only hardware between the mail server and the world is a switch and a dsl modem. I doubt the error from OE would help, but here it is: Code: Your server has unexpectedly terminated the connection. Possible causes for this include server problems, network problems, or a long period of inactivity. Account: 'mail.mydom.ain', Server: 'mail.mydom.ain', Protocol: SMTP, Port: 25, Secure(SSL): No, Socket Error: 10053, Error Number: 0x800CCC0F I should probably also include this: Code: [[email protected] An update to this: the telnet above was from localhost. When trying to telnet from outside to the SMTP port, the session resolves the IP address correctly and attempts to connect, but hangs for a couple of minutes and returns a connection timed out error. Any ideas what's up with this?