Linux professionals might describe themselves as "certified geeks." But this term is becoming more serious as IT professionals look to organized certification and educational programs to boost their Linux knowledge and marketability.

The ubiquity of certification programs for Cisco, Microsoft and Novell  products reflects the popularity of those technologies. And as Linux usage increases in corporate networks, interest in open source certification and education is climbing.

Demand for employees with Linux skills can be correlated with Linux's expanding presence in corporations, observers say. According to IDC, Linux accounted for 23% of new server software shipments last year, almost twice as much as Novell NetWare and Unix combined, and behind only Windows. Open source servers running Apache Web Server and Linux also are said to be the most-used software combination for running Web servers, according to Netcraft, an Internet research firm.

Independent companies that provide training, testing and certification for Linux include CompTIA, SAIR and the Linux Professional Institute (LPI), along with vendor-specific certifications, such as the Red Hat  Certified Engineer program.

Novell also has started offering Linux education as part of its certification process, as the vendor incorporates more Linux technology into its products. IBM  also offers certifications for some of its commercial software products on Linux, such as DB2 database and WebSphere application server.

Some of the most popular certifications are LPI's Level 1, 2 and 3 programs. The programs are a hit with Linux users because they were created and are conducted similarly to the open source model, in that no one vendor dominates the training. Input on the program also comes largely from its alumni.

"LPI was borne out of a community development process," says Evan Leibovitch, LPI's president. He says this is what makes it different from vendor certification programs. "Different automakers don't give out driver's licenses for their own cars, and you wouldn't trust a pharmacist who received an education from a drug company," he adds.

LPI gave out 10,000 exams from its inception in 2000 to May 2002. Since last year, the firm had administered another 10,000 exams.