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Relaying denied, IP name possible forged

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jcrapps

Programmer
Oct 26, 2001
94
US
Hello,

Some of my clients are receiving an undeliverable when trying to send out an email. It only happens rarely, but enough to want to investigate it. The body of the undeliverable looks like this:

-----------------------------------------------------
Your message did not reach some or all of the intended recipients.

Subject: Blah Blah
Sent: 1/15/2009 10:59 AM

The following recipient(s) could not be reached:

'John Doe' on 1/15/2009 10:59 AM
550 5.7.1 <jdoe@foo.com>... Relaying denied. IP name possibly forged [123.123.123.123]

------------------------------------------------------

Here is our current setup:
Mail server is an in house Exchange Server 2007 which is a standalone.
Our clients are using Outlook 2002-2007. We have two mail servers. One is our primary and the other is a backup, which is a POP server hosted in the cloud. The primary mail server is the default Outlook profile when sending, but I have noticed that this error message will not occur if I explicitly set it to send via our primary mail server under "Accounts" in Outlook. This leads me to believe that it has something to do with our secondary mail server somehow sending it by default instead of the primary. Not sure. The IP address that's listed in the error message above is the IP of our Sonicwall firewall, which we replaced a few months back. I didn't notice this error message before then, but I'm not 100% sure it happened exactly when we replaced it.
 
Oh yeah, I forgot to mention that we're using a Barracuda SPAM firewall to filter messages before they hit the Exchange Server.
 
Also, the IP address 123.123.123.123 is the global IP of our Sonicwall firewall.
 
Anyone have any clue here? Where can I start to troubleshoot this issue?
 
I had a similar issue. None our clients could send to Yahoo, or could browse Yahoo website. When sending mails to yahoo, they received "550 relay not permitted". I removed forwarders, and restarted DNS Service, problem solved.
I hope it may help you.
 
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