Palo Alto Networks

Founded: 2005
Headquarters: Alviso, California
Funding: US$28 million from Globespan Capital Partners, Greylock Partners and Sequoia Capital
CEO: Dave Stevens
What the company offers: The PA-4000 Series network devices, introduced in June, which use a so-called App-ID application-classification technology to inspect about 450 applications traversing the PA-4000 hardware and apply security rules to these applications.
Why it's worth watching: Enterprises are frustrated with their traditional perimeter firewalls, because firewall ports increasingly are opened up to allow business traffic, particularly over Port 80. The PA-4000 line is offered as a transitional technology that works behind traditional, port-based firewalls to monitor applications and apply security rules to them.
How the company got its start: CTO Nir Zuk worked on some of the earliest firewalls at Check Point Software and later founded OneSecure, which was acquired by NetScreen Technologies, later acquired by Juniper Networks. Over time, Zuk observed that the relationship between ports and applications was diminishing, and he devised a method to look at the content itself through a new type of firewall he had invented.
Where the company got its name: Zuk, who selected it, reportedly lives in Palo Alto, California
Customers: Constellation Energy and Mercy Hospital in Baltimore, and the city of Seattle.

Provilla

Founded: February 2005
Headquarters: Mountain View, California
Funding: US$10 million in private funding; investors include Hitachi Systems
CEO: Antonio Espinosa
What the company offers: The LeakProof data-leak prevention product, released in January 2007.
Why it's worth watching: LeakProof isn't the first product to prevent the unauthorized transmission of sensitive content. However, Provilla's founders, who hail from Chinese universities but are developing the product in the United States, think they've come up with a better mousetrap: their DataDNA fingerprinting technology that scans file servers to create a signature for each document. Cosmopolitan in its outlook, Provilla's software supports the Japanese, Chinese and French languages in addition to English, as the founders look to building an international customer base.
How the company got its start: Co-founder Fei Huang was principal engineer at Sygate (later acquired by Symantec), which designed one of the earliest host-based network-access-control products. Huang teamed with Liwei Ren, a mathematician specializing in algorithms and pattern-matching, to come up with a desktop agent to detect unauthorized use of sensitive data.
Where the company got its name: "Pro" stands for protecting, and "villa" is Latin for village, so the name indicates that the company's technology protects a community of people.
Customers: Orchard Supply Hardware, Richard Fleishman & Associates, Sony-Ericsson Chinese joint venture. Distribution agreement with BigFix and Reconnex.

Robot Genius

Founded: 2005
Headquarters: Oakland, California
Funding: US$2 million from Kingdon Capital and Venio Capital Partners
CEO: Stephen Hsu
What the company offers: Syberus behavior-based malware-detection client software, an antimalware browser plug-in and the RGcrawler Web-crawling technology that looks for malware executables on the Internet.
Why it's worth watching: Although signature-based antivirus technology has a venerable history defending against known threats, the security industry is looking at other methods, such as behavior-based defenses that identify and block threats based on behavior. Robot Genius has come up with its own approach to malware detection to determine unsafe executables, and it could get picked up by the larger industry under a licensing plan.
How the company got its start: Hsu and CTO James Hormuzdiar teamed on start-up SafeWeb, sold it to Symantec for $26 million in 2003, and decided to continue working together to found another company to develop a new way to protect against malware.
Where the company got its name: Implies the technology's ability to replicate automatically the downloading and testing of executables off the Internet.
Customers: Not disclosed.