Postfix 5xx Reject relay denied

Posted July 26, 2014 2.5k views

I’ve noticed the last few days this number going from around 30-75 for “5xx Reject relay denied 100%”, which is higher than normal. I’m not sure what it really means specifically and was hoping someone could shed some light on it.

An examlpe detail line for this is:


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Somebody, probably a spambot, is hoping you’re running an open relay to help give their messages some air of legitimacy. As it happens, you’re not running an open relay, and those entries in the log are just informing you of messages that were not accepted for relaying, just in case you really did want to relay them.