What does error 454 Relay access denied mean?

Posted on 2008-06-26
Last Modified: 2013-11-30
I have a client who is getting the message "relay access denied" . How do I know if this error is occuring because of his exchange or ours. I should also mention that its intermittent, some of his emails are getting through to us and some aren't.
Thanks for your help,
Question by:cireduran
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LVL 58

Expert Comment

ID: 21877938
That error does not sound to me like it is an Exchange Server error at all. It sounds as if there is some other server which is handling the mail between the sender and the recipient which is causing this error - perhaps the ISP's server?

Expert Comment

ID: 21878829
Any further details of the error message?  Was there a x.x.x SMTP error code as well?  Anything different between messages that make it and messages that don't?  

The 454 is usually an authentication issue so, for instance, an auto-generated email (ie a contact form from a webpage) that does properly authenticate Exchange could yield an error like this.

Author Comment

ID: 21879377
The messages are being sent from an external company to our company. When someone at the other company sends us an email. they are getting this error. I didn't think it would be an issue with my exchange but I wasn't completely sure. The company's domain is not blacklisted and they are able to send some emails through intermittently.
Thanks for your help,
If I can answer anymore questions please let me know.

Expert Comment

ID: 21879497
I was thinking the specific SMTP error code might give us a little more insight into the cause of the rejection.  I would be looking for similarities (formatting/content) in the messages being rejected.  Check the headers to determine if your MTA is rejecting the messages.  If not...really not your problem.  If so...what kind of filtering are you using?  Are you using Intelligent Message Filter, for instance, and it is causing the rejection?  For that you could simply provision the IP of the mail server from the other company as being allowed...this will bypass the filter for messages from that server.  Otherwise you'll have to delve into attributes of each message to determine why your filter would reject some but not all.  Usually...that's content/MIME/formatting stuff.
LVL 58

Accepted Solution

tigermatt earned 500 total points
ID: 21881408
Unless you've got some form of device or anti-spam software perhaps which is sitting between your Exchange Server and the Internet, there's no reason why Exchange would generate that message. If Exchange receives the mail direct, then it would generate a slightly more friendly error than that error, which sounds to be one produced by the Linux mail servers.

Unless all that isn't true and you do have anti-spam hardware, then you need to find out where the mail is being blocked by looking in more detail at the NDR. It should give you the name of the server creating the bounceback, so you can track it down.

I expect you will find it is at the remote end that is causing the issue.


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