Barracuda Networks Mail Transport and Policy

The Barracuda Spam Firewall features a robust Message Transport Agent (MTA) capable of handling high SMTP connection and mail delivery volumes. For inbound protection, the MTA includes a number of built-in protections, including rate controls, IP reputation analysis, sender authentication, and recipient verification, which allow rejection of SMTP connections before actually receiving any messages itself.

For relaying outbound mail, the Barracuda Spam Firewall supports access controls and SMTP Authentication to ensure that the Barracuda Spam Firewall can safely relay email without risk of acting as an open relay. The outbound mail relay can also perform rate control checks based on sender IP address or sender email address.

The Barracuda Spam Firewall MTA also supports a built-in journaling function for use with message archivers.

Per-user Policy Control:

Built for the diverse needs of small and medium businesses, enterprises, educational institutions, government institutions, and ISPs, the spam scanning engine of the Barracuda Spam Firewall supports granular policy at the individual user level. Depending on the model of Barracuda Spam Firewall, many spam scanning features including block lists (“blacklists”), allow lists (“whitelists”), quarantine capabilities, scoring thresholds, and Bayesian analysis, can be customized for each email user. This per-user policy control offers another level of granularity above competing systems which may only offer policy controls at a user or domain level.

Encryption:

To encrypt email traffic between sites across the Internet, the Barracuda Spam Firewall MTA supports TLS (Transport Layer Security). SMTP/TLS email traffic is encrypted over the Internet using SSL (Secure Sockets Layer) and can be used between Barracuda Spam Firewalls or in conjunction with other popular email servers such as Microsoft Exchange that support SMTP/TLS. Unlike end-to-end encryption techniques that typically require special client software, SMTP/TLS is gateway-based encryption that is transparent to users. Moreover, because internal email traffic remains in the clear, content-based policies can still be enforced at the gateway prior to encryption.

Hardened Operating System:

Based on the popular Linux open source kernel that has stood up to scrutiny among security researchers, the Barracuda Spam Firewall operating system is hardened for maximum security and stability. In addition to thorough internal testing, Barracuda Networks credits the community of “white hat” security researchers that continually work with security vendors to uncover and resolve potential vulnerabilities in both the Linux operating system and its associated utilities. While the vast majority of technology in the Barracuda Spam Firewall is proprietary, Barracuda Networks seeks to leverage secure and functional open source alternatives whenever possible.