Applies to all Barracuda Spam Firewalls, firmware versions 3.5.11 and below.
If a message is blocked for reason of Fake Sender Domain, it means that the Barracuda Spam Firewall could not do a successful lookup on the A record or MX record of the sending domain name. If an A record is not present, the Barracuda will fall back to looking up the MX record. If neither of these are found, it will reject the email with the reason Fake Sender Domain.
Fake Sender Domain rejections can be disabled on the Advanced > Email Protocol page of the Barracuda Spam Firewall's web interface; set the Reject Fake "From:" Domains option to No to disable them.
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