Barracuda Networks, Inc. is a privately held company providing firewall products to block e-mail spam, viruses, spyware, load balancing and instant messaging software.

Barracuda Networks was established in 2002 and since June 2007 is based in Campbell, California, having previously operated in Mountain View, California and Cupertino, California.

The company's first offering and premier product is the anti-spam appliance named Barracuda Spam Firewall - a dedicated firewall computer running a hardened Linux-based system. Released to the market in October 2003, it has since won several awards from trade publications. The product accepts SMTP traffic and analyzes the source and content of each inbound e-mail message, then makes a decision to allow, tag, quarantine, or block. Allowed and tagged traffic is passed on to the next SMTP system in the path, typically an organization's MTA. Several models are available to support different levels of traffic and numbers of domains. Systems can cluster to allow for increased capacity and/or fault tolerance.

The Barracuda Spam Firewall utilizes twelve defense layers to protect downstream mail servers from exposure to spam and viruses. The first five defense layers are connection management layers, including Denial-of-service attack prevention, rate control, IP reputation analysis, recipient verification, and sender authentication. When blocking at the connection management layers, the Barracuda Spam Firewall simply drops incoming SMTP connections prior to receiving messages.

For the remaining seven defense layers, the Barracuda Spam Firewall receives the messages and scans their content for spam and viruses. The mail scanning defenses include virus scanning, customer-defined policy, fingerprint analysis, Intent analysis, Image analysis, Bayesian analysis, and rules-based scoring. Customers can choose to configure the Barracuda Spam Firewall to either send or suppress bounce messages to senders when blocking email. To avoid backscatter, Barracuda Spam Firewalls running firmware release 3.4.10.100 and higher suppress any bounce messages to spoofed sender email domains identified through Sender Policy Framework (Barracuda Spam Firewalls running earlier firmware releases do not have SPF bounce protection).

In April 2005 the Barracuda Spyware Firewall was released to the market. On 2006-08-15 Barracuda renamed the device to the Barracuda Web Filter to reflect the more general web content filtering capabilities that had been added to the product since its introduction. In January 2006, it closed its first outside investment of $40 million from Sequoia Capital and Francisco Partners. Sequoia Capital, which has provided financing to Cisco Systems, Google, Netscreen, and Yahoo!, is widely viewed as the world's preeminent venture capital firm. Francisco Partners, whose founders include technology investment banking pioneer Sandy Robertson, is a leading private equity firm with tremendous experience in financial and deal structuring.

In September 2005 Barracuda announced the Barracuda IM Firewall at a conference. In February 2006 it was released in the United States, and it was released in Europe in March 2006.

In November 2006, Barracuda Networks launched the Barracuda Load Balancer. The Barracuda Load Balancer provides IP network traffic management across multiple servers and features Layer 4 load balancing, Layer 7 cookie persistence, and SSL acceleration.

On January 29, 2008, Barracuda Networks was sued by Trend Micro over their use of the open source anti-virus software Clam AntiVirus, which Trend Micro claims to be in violation of their patent on 'anti-virus detection on an SMTP or FTP gateway'..

Controversial "backscatter" problems

Because of a problematic default configuration of older servers, Barracuda Spam Firewalls are accountable for backscatter (indiscriminately bouncing emails) to various users. Certain servers today may cause some users to receive many bounces/day from Barracuda Spam Firewalls, because spammers forge these users' address in the "From:" field and Barracuda indiscriminately replies to such messages. The problem with the Barracuda system originates in the fact that Barracuda seems to do much of its spam analysis only after closing the connection to an incoming mail server. Many other systems do much more "spam/no spam" analysis of incoming messages before closing the incoming data connection, meaning that they are able to instantly report an email as not deliverable to the sending mail server, instead of being forced to try to inform a (forged, and therefore almost certainly innocent) "From:" email address after the fact. As a counter example, Gmail does an excellent job of filtering spam, but produces almost no backscatter since it either drops the incoming connection before receiving the full email, or tells the originating (hijacked) mail server that it will not deliver a specific message.