Sender Authentication

The Barracuda 4th layer of protection against email borne threats is the Sender Authentication which includes defining Sender policy framework (SPF) which works by having domains publish reverse MX records to display which machines are designated as mail sending machines for that domain. When receiving a message from a domain, the recipient can check those records to make sure mail is coming from a designated sending machine. 

 

Selecting Yes means that the Barracuda Email Security Gateway will query DNS for the SPF record for the sending domain to verify if the sender is the true owner of the sending domain or not. 

• Another sub layer of protection is the DKIM which allows a sending domain to cryptographically sign outgoing messages, allowing the sending domain to assert responsibility for a message. When receiving a message from a domain, the recipient can check the signature of the message to verify that the message is, indeed, from the sending domain and that the message has not been tampered with. 

 

• If a domain is registered at http://EmailReg.org, the Barracuda Email Security Gateway will allow all email from that domain. If, however, you want all email from any domains that are registered at EmailReg.org to undergo header, subject and body filtering, you can add them to this table as an exemption to that rule. If you put any domain in the Blocked Sender Domain/Subdomain table that is ALSO registered at EmailReg.org, the Barracuda Email Security Gateway will block all email from that domain. 

 

• Invalid Bounce Suppression is designed to reduce the number of bounce messages to forged return addresses. All email sent out through the Barracuda Email Security Gateway contains a return address tagged with an encrypted password and expiration time. Any bounce notice that does not include this tag is blocked and recorded in the Message Log with the reason "Invalid Bounce".