NDR: "A configuration error in the e-mail system..."

[Anett]

Hi

We seem to have a problem when one of our users recieve messages from
one specific remote sender. The messages are delivered all the way to
the back-end server, but there a NDR is created:

"A configuration error in the e-mail system caused the message to
bounce between two servers or to be forwarded between two recipients.
Contact your administrator."

This is only happening when the messages is addressed to a send list,
not when it is addressed directly to the user.

We are running Exchange Server 2000 and Outlook 2002.

I hope someone can help me in this matter.


Regards

Anett

 

[Brian Tillman]

We seem to have a problem when one of our users recieve messages from
one specific remote sender. The messages are delivered all the way to
the back-end server, but there a NDR is created:

"A configuration error in the e-mail system caused the message to
bounce between two servers or to be forwarded between two recipients.
Contact your administrator."

This sounds like a message a sender would receive, not a recipient. It's
the result of two mail routers thinking that each is the forwarder for
itself; i.e., router A thinks that in order to reach the recipient, router B
must handle the message and router B thinks that A should handle the
message.

Who sent the original messge that elicited this NDR and who received the
NDR?

 

[Anett]

This sounds like a message a sender would receive, not a recipient. It's
the result of two mail routers thinking that each is the forwarder for
itself; i.e., router A thinks that in order to reach the recipient, router B
must handle the message and router B thinks that A should handle the
message.

Who sent the original messge that elicited this NDR and who received the
NDR?

Sorry for my indistinct description. The NDR is, off course, sent back
to the original sender.

Anett

 

[Brian Tillman]

Sorry for my indistinct description. The NDR is, off course, sent back
to the original sender.

That's what I thought. Is the NDR generated by your mail server or one
outside of your system? If the latter, you have no hope of addressing the
issue.

 

[Anett]

That's what I thought. Is the NDR generated by your mail server or one
outside of your system? If the latter, you have no hope of addressing the
issue.

The NDR is created by our back-end server and sent out.

Anett

 

[Brian Tillman]

The NDR is created by our back-end server and sent out.

Are you sure your server is generating it or is it just passing it back to
the original sender from an upstream router?

Are the sender and recipient addresses on separate machines? If the router
producing the error is in your domain, then that machine is talking to
another router that it thinks is upstream from it and that other router
thinks the original is upstream so they hand the message back and forth
until the maximum hop value is exceeded causing one of them to report the
NDR to the sender. Is the original message appended to or included in the
NDR? If so, the Received-by headers should tell you which teo machines are
arguing.

 

[Anett]

Are you sure your server is generating it or is it just passing it back to
the original sender from an upstream router?

Are the sender and recipient addresses on separate machines? If the router
producing the error is in your domain, then that machine is talking to
another router that it thinks is upstream from it and that other router
thinks the original is upstream so they hand the message back and forth
until the maximum hop value is exceeded causing one of them to report the
NDR to the sender. Is the original message appended to or included in the
NDR? If so, the Received-by headers should tell you which teo machines are
arguing.

According to the information in Message Tracking Center (Exchange
System Manager), the message is transferred from the front end server
to the back end server, and then the NDR is generated.

It's an external sender on a different domain. The original message is
not included in or appended to the NDR.

The thing is the problem occurs only when the mail is addressed to a
send list, not when the sender is addressing it directly to the
recipient. That's why we can't figure out what's wrong. Why it is ok in
one case but not in the other...

Any idea?

Anett

 

[Brian Tillman]

I received the same NDR but what worries me more is that I received 3
bounced emails as shown below but no one in our company sent these
emails as you can tell from the subject line that the email sent is
obviously spam.

What I am concerned about is that our Server has been hijaked and is
sending out spam?

It probably hasn;t been hijacked. I think two things are happening here.
The first is that your address has been hijacked and the second is that the
mail routers at company.com are misconfigured or that "name" forwards his
mail to someone and that someone forwards it back to name.