Spam bypasses Anti-spam Service

[CrazyLane]

I use an Anti-spam service that uses an MX record that points to the service, passes through the appliance, then it is relayed to our server.

Every once in awhile I get a spam message that seems to ignore the mx record and is sent directly to the server.

Any idea how this happens? It is not being sent locally as the sending IP is usually from far away. In the headers of the spam message there is no record of it passing through the appliance.

 

[nobaloney]

It happens because spammers sometimes use A records. They don't care about proper procedure or protocol; they only want to deliver spam.

If you know enough about firewalling you can block traffic on port 25 from all servers except your mx server.

Jeff