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Barracuda – Mail Protocol Violation

A customer updated the firmware from a Barracuda SPAM &Virus 300 firewall. The firmware was upgraded from version 3.4 to version 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.

Secret Barracuda Spam firewall options

While troubleshooting a Barracuda Spam Firewall 300 I found a forum on internet, which shows you how to get an extra tab under the Advanced configuration of the Barracuda Spam Firewall. The “secret” configuration page is enabled with the following steps:

  1. Logon to the Barracude Spam Firewall 300;
  2. Click on the Advanced tab;
  3. Add &expert=1 at the end of the URL and hit enter;

You will now get the extra tab Expert Variables like shown below.