Cisco is still dominating the networking market, and there’s no doubt about it. The newly published Worldwide Quarterly Security Appliance Tracker report by IDC found that the company raked in 16.2 percent of the $2 billion generated by the security appliance industry generated in the third quarter of 2012.

Cisco maintains a firm lead over Check Point, which IDC listed as the second largest vendor by factory revenue with a 12.8 percent share, in spite of a 17.3 percent decline from last year.  But Check Point in comparison has seen sales increase by 12.8 percent.

Fortinet is the third largest player in this space and by far the fastest growing among the top five vendors, with a 17.2 percent revenue gain from Q3 2011. Palo Alto Networks and Sourcefire, number four and five on the list, have also seen aggressive sales growth.

Together with Cisco and Check Point these three companies represent 48.5 percent of the market, which grew a mere 5.7 percent in the 12 months leading up to IDC’s study.

“Overall, macroeconomic conditions have been questionable at best. While the security market remains more resilient than others, there was a definite slow-down in growth rates in the third quarter,” IDC research manager of security products John Grady said in a statement. “That being said, the evolving threat landscape continues to drive spending on security products as organizations battle to keep their infrastructures secure and their data protected.”

Cisco is losing share in network security, but it hopes to make it up by gaining a reasonably early start in the SDN space. The company is targeting its legacy customers by incorporating software-defined components into existing products such as the operating systems that are used to power its carrier-grade routers.