Network hardware and software vendor F5 has bought Defense.net, a security startup with cloud-based service for blocking distributed denial of service (DDoS) attacks that hit lots of servers and can bring down websites.

As a result of the deal, F5 will bolster its software lineup, which includes software for staving off DDoS attacks that hit companies’ on-premises data centers.

Barrett Lyon, who also founded DDoS mitigation company Prolexic, started Defense.net in late 2012. (Content-distribution network company Akamai bought Prolexic last year.) Lyon also was a character in the cyber thriller “Fatal System Error” by Joseph Menn.

DDoS mitigation has been hot lately. CloudFlare, which offers DDoS mitigation alongside other services, announced $50 million in funding in December. And two months earlier, Google announced a services for stop DDoS attacks from hitting the servers of non-profit organizations and other groups.

That makes sense as DDoS attacks on companies continue to get hit with DDoS attacks. Recent victims include Dwolla, SendGrid, and games like Battlefield 3.

Terms of the deal were not disclosed in F5’s statement about the acquisition.

Belmont, Calif.-based Defense.net raised $9.5 million in venture funding last summer. Bessemer Venture Partners led the round.

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F5 Networks is the global leader in Application Delivery Networking. The company’s hardware, software, and virtual solutions help organizations address the relentless growth of voice, data... All F5 Networks, Inc. news »

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Defense.net Founded by Barrett Lyon, who created the Distributed Denial of Service (DDoS) attack mitigation industry more than 10 years ago, Defense.Net has combined the top minds in the DDo... All Defense.net news »

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