Procure o recurso Barracuda "Varredura de cabeçalho profundo" . Dependendo da sua unidade e da revisão do firmware, é provável que esteja mascarado com IP Configuration
> Trusted Forwarder
configuração.
Trusted Forwarder Configuration
Enter the IP addresses of machines that you have set up to forward email (i.e. Trusted Forwarders) to the Barracuda Spam & Virus Firewall from outside sources. The Barracuda Spam & Virus Firewall exempts any IP address in this list from Rate Control, SPF checks and IP Reputation. In the Received headers, the Barracuda Spam & Virus Firewall will continue looking beyond a Trusted Forwarder IP address until it encounters the first non-trusted IP address. At this point, Rate Control, SPF checks and IP Reputation checks will be applied.
Isso costumava ser um recurso separado, mas no changelog v5.1, o Barracuda o removeu da interface do usuário:
Mail Processing
The Deep Header Scan setting for use with Trusted Forwarder IP addresses has been removed from the web interface, as this functionality is now part of the Trusted Forwarder feature.