Fixed font Subject: Outlook 2003 ignores [E]SMTP welcome banner and refused to send mail. (Receiving works fine through POP)
Author: Chris Miller Date: 05 Nov 2009
References:
Hi Folks,

I'm running Outlook 2003 (SP3). Outlook is not recognizing the SMTP
greeting from the mail server and as a result terminates the connection
without doing anything. I have tried all combinations of:
PORT: 25, 587
AUTHENTICATION: Required, Optional (Plain Text, NTLM, GSSAPI)
ENCRYPTION: Required, Optional (TLS - Self-signed Certificates)

None work. I would expect I should be able to at LEAST get port 25, no
authentication, no encryption to work, but no dice.

I have reviewed the interaction between Outlook 2003 and the mail server
with a packet sniffer and it is clear that the server issues a 220 greeting
message and Outlook 2003 summarily "RST"s the connection. Now, that's just
anti-social.

I know this appears to be a reasonably wide-spread problem because I can
find many questions about how to solve it, but I find no solutions. I
suspect that it is simply a matter of Outlook 2003 expecting to see
something in the banner that he doesn't see and I need to know what that is.
Can anybody shed some light on this?

Thanks for the help,

Chris.