Incoming email must be a reply, cannot initiate new email

[Datanomics]

Environment: Windows 2003 running Exchange 2003

I'm completely confused on this one:

I have someone outside our domain who cannot send an email IN to our domain UNLESS he is replying to an email that was sent FROM our domain. If he starts a new email (vs a reply) he will receive a bounce-back (Note: ##.###.###.## is the external IP addy of my Exchange server):

"##.###.###.## failed after I sent the message.

Remote host said: 552 4.3.1 Message size exceeds fixed maximum message size"

This will occur even if the email is only a few KB!! As far as I know, this is an isolated case but I'm going to guess that other people have encountered the same problem but I've just never been notified...

I am STUMPED!!!! Any help & guidance would be greatly appreciated! Thanks in advance!

********************************

Note: This is NOT a cross-post. This is the one & only place this question / problem is posted.

 

[tpulley]

A couple of things to check. Do you have a mail filter in place? Check the events/logs and settings there to see if there are any restrictions on there blocking it.

If you have a mail filter try putting them on the whitelist and see if that fixes it.

Make sure the limit size is correct. If its for just one user then ignore this, it doesn't change per site.

If its only one person on the outside, I would suspect their sending mail server.

 

[PcLinuxGuru]

I recently ran into a similar issue where a fellow tech changed a number on me.

In your SMTP connector properties under Messages are the hard limits. The one your probably wanting to look at is the first one. You can try unchecking the box thus removing the limit (even if it's just for test purposes.) My co-worker set it to 0 thinking zero meant unlimited and all SMTP traffic stopped.

 

[Datanomics]

Thank you both for your replies...

If you have a mail filter try putting them on the whitelist and see if that fixes it.
-- Only using IMF & McAfee AntiSpam module via GroupShield. I was going to add the sender's email server to IMF's accept list but there are about 2 dozen server IPs. And since I'm receiving replies would that really make a difference, you think?

If its only one person on the outside, I would suspect their sending mail server.
-- As far as I know, yes, this is an isolated problem with this one user / domain (which is his own personal domain - not a large domain e.g. NFL.com, Verizon.com, etc.). Ohhhh... I wonder if it's failing on the SMTP reverse dns lookup thereby denying the email....!