SMTP Server: '421 unable to verify sender domain'

Posted by Tim on Server Fault See other posts from Server Fault or by Tim
Published on 2009-04-28T21:49:33Z Indexed on 2010/04/02 15:03 UTC
Read the original article Hit count: 308

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windows-server-2008

|

smtp

I have recently setup a new SMTP server on my new webserver (win 2008).

The server sends mail from a number of domains hosted on the website, everything seems to work OK but I am getting a number of undeliverable reports which state '421 unable to verify sender domain'

What does this mean and what should I do about it?

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