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Barracuda – Mail Protocol Violation

September 8th, 2009

A customer updated the firmware from a Barracuda SPAM &Virus 300 firewall. The firmware was upgraded from version 3.4 to version 3.5.12.024. After the upgrade no email was coming in or going out through the Barracuda firewall.

All email was blocked and the following reason was visible in the message log:

Mail Protocol Violation

At first I couldn’t find a reason why all mail was blocked, so I contacted Barracuda and established a remote connection with Barracuda for remote troubleshooting. (I really like that feature). Finally the engineer found the problem. The Maximum Message Size value under Advanced – Email Protocol – SMTP Configuration was set to:

100000000000000000000000000000000000000 bytes

Yep, you read that correctly. I have no idea where that value came from. So I changed it back to the recommended value of 100 MB. After changing the value, mail started coming in and going out again through the Barracuda.

René Jorissen works as Solution Specialist for 4IP in the Netherlands. Network Infrastructures are the primary focus. René works with equipment of multiple vendors, like Cisco, HP Networking, Juniper Networks, RSA, PaloAlto Networks, Microsoft and many more. René is CCNA (Routing & Switching, Security), CCNP , Cisco ASA Specialist and CEFFS certified. You can follow René on Twitter and LinkedIn.
René Jorissen
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