Spam relaying problem

[Goatman88]

Recently we've been seeing spam being relayed off our front end server. I've checked and double-checked to make sure the settings are correct such that we are not an open relay. I was also able to confirm our non-relay status on MXToolbox.com. Yet I'm still seeing all this garbage going through which is clogging up the system and getting us black listed.

Has anybody experienced this before?

 

[Zelandakh]

If emails are being routed through your server then you ARE an open relay.

Test it with telnet on port 25 to the FE yourself.

 

[smah]

If you're certain that you're not an open relay, perhaps it's not the front end server that's the problem; maybe there's a local computer on the network that is compromised.

 

[Zelandakh]

Check the headers of the messages in the queue for the source IP which will confirm that, good thinking smah.