David and Eric,
We have an Exchange server as well and we also have a hardware appliance
that does our spam filtering/virus scanning for us. I have noticed on a
few occasions that we have gotten Sender Timeout errors from some
trusted senders. One of these situations happened yesterday from a
Comcast address. The sender complained that they received an NDR when
sending an e-mail to someone on our Exchange server. I checked our spam
filter and could see in the logs that it wasn't blocked, it had "Sender
Timeout" listed every time that they would attempt to send an e-mail to
our user.
Unfortunately, I cannot read header information for those messages that
have Sender Timeout errors to read into this further.
I believe the other recent problem was with one AOL address sending us
e-mail. Sometimes it would work. I would see may 3 or 4 out of 20 make
it through. Others had the timeout error.
Javier
-----Original Message-----
From: MSU Network Administrators Group [mailto:[log in to unmask]] On
Behalf Of Vietti, Dave
Sent: Wednesday, March 21, 2007 11:24 AM
To: [log in to unmask]
Subject: Re: [MSUNAG] qmail/Exchange question
Eric,
We have what appears to be a similar problem but a slightly more
complicated scenario. We have a third party vendor doing SPAM
processing for us. Occasionally, we receive a message that the third
party is unable to deliver. The third party indicates that our Exchange
Server times out on multiple delivery attempts.
So far what seems to be common is:
- the messages have been forwarded (both automatically and manually)
- the original message was likely automatically generated by a system
An example is, I make an order and use my MSU mail address which is
forwarded to my Exchange Server. An E-mail message is sent as a result
of the transaction. This is the type of message that appears cause the
behavior. I've also seen the behavior with forwarded automatically
generated advertisements. The interesting part is from the same sender
some make it through and some don't.
The SPAM processing vendor sends me a message when they can't deliver a
message like this which is how I've gathered the information on the
behavior. I'd be happy to share some of those with you if it would
help. Until your message, I've thought the third party SPAM processing
company was part of the problem but your message makes it point to the
Exchange Server.
I suspect somehow the problem is content related. While not conclusive,
some minimal testing would suggest that the problem goes away if I take
the forwarding out of the picture.
We'll share anything we find out.
******************************
David Vietti
Systems Administration Manager
Michigan State University
Physical Plant Division
Room 1 Physical Plant
East Lansing, MI 48824
(517)432-0240 Office
(517)353-5001 fax
[log in to unmask]
******************************
-----Original Message-----
From: MSU Network Administrators Group [mailto:[log in to unmask]] On
Behalf Of Eric Weston
Sent: Wednesday, March 21, 2007 10:00 AM
To: [log in to unmask]
Subject: [MSUNAG] qmail/Exchange question
Here in the Library, we run a MS Exchange Server. One of our staff has
been having an issue with email from a non-MSU sender bouncing. This
appears to happen only with replies from the non-MSU party to our staff
person's email. The error messages indicate that the email is reaching
our exchange server, but time out before our exchange server accepts it.
The sender's email is issued from a qmail MTA on an email server hosted
by GoDaddy.com. We know of no other cases like this. Has anyone
experienced or know of a similar case of qmail and Exchange having a
conflict? Email protocols are not one of my things, so I'm flying blind;
any ideas are appreciated.
Eric Weston
--
^V^V^V^V^V^V^V^V^V^V^V^V^V^V^V^V^V^V^V^V^V^V^V^V
Eric Weston, M.F.A.
Information Technology Professional
Michigan State University Libaries, Systems Unit
http://www.msu.edu/~westone
"Time flies like an arrow; fruit flies like a banana."
-- Groucho Marx
