501 error

Posted on 2009-04-15
Last Modified: 2012-05-06

A couple of my users are getting an bounce when sending messages to some people. It seems random as they have been able to send other messages to the same recipient and other users are able to send the same message to the same recipients. (If that makes sense)

The NDR is
There was a SMTP communication problem with the recipient's email server.
5.5.0 smtp;501 Rewrite failure, please try again later

I'm guessing this is a temp glitch at the time of sending (rather than config problem) but as I can't find any info on this particular message, I'm at a loss. If somebody can shed some light on this problem or point me in the direction of some information, it would be greatly appreciated.

We use
Exchange 2003 6.5.7651.61 SP2
Windows 2003 R2 Std Edition SP2
We use McAfee Enterprise v8.7.0i

And Clearformat email branding, with Postini filtering behind them.

Question by:memikeec
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LVL 65

Expert Comment

ID: 24147120
That is not an Exchange message. How do you route outbound email? It will be something in that path after Exchange has handed off the message to the next hop.


Author Comment

ID: 24147366
Mail is routed to a smarthost, but that host doesn't store the messages, my own Exchange servers handle the queues. The smarthost checks the end recipient to ensure that it is available, if so it will accept the message and make a connection to the recipient server.
LVL 65

Expert Comment

ID: 24147531
The complete NDR isn't an Exchange message. Exchange doesn't write NDRs in that style. Therefore the problem is further down the chain.
As for the cause of the problem, that is probably internal to a system somewhere in the chain. While your smart host may not store the message, it will accept it and have to store it at least temporarily so that it can write its own headers to the message. That may well be where the error is occurring.

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Author Comment

ID: 24147587
Thanks for your reply Simon.

Apologies, I didn't include the whole NDR in my original post.

There was a SMTP communication problem with the recipient's email server.  Please contact your system administrator.
            < #5.5.0 smtp;501 Rewrite failure, please try again later>

This looks like an Exchange message to me, what do you think?

You may also be right about it being a problem further down the chain.
LVL 65

Accepted Solution

Mestha earned 125 total points
ID: 24150672
Still not an Exchange message. All it means is that the failure has occurred on the next hop and the Exchange server was forced to generate the NDR. That is the most efficient way of dealing with non-deliverable messages.

The reason I know it isn't an Exchange message is because Exchange 2003 does not have any kind of rewriting functionality.


Author Closing Comment

ID: 31570336
Thanks Simon.

I've since found out that it was a problem with our upstream provider. They believe the issue is now resolved.

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