Editor's Note : On Dec. 4, this newsletter will shift its focus from VPNs to network access control. NAC is an emerging network security architecture that starts with securing endpoints before they connect to networks and extends to monitoring and controlling their activity after they have been admitted. There are working NAC products today, but most vendors committed to NAC are still fleshing out their products, which makes it an area that warrants a newsletter of its own. Along with the shift in focus comes a new, intuitive name: the Network Access Control Newsletter. We hope you find it useful. Network World and networkworld.com will continue to cover VPNs as part of our regular news coverage. Thanks for reading.

Even as its dominance wanes, and SSL VPNs become more popular, Juniper continues to sell more SSL VPN gear than its nearest competitors.

According to new security research by Synergy Research Group, so far this year Juniper is responsible for 27.2% of all SSL VPN sales worldwide, with Citrix in second, F5 in third, Aventail in fourth and Nortel in fifth.

Juniper has held the lead over the rest of the field since the fourth quarter of 2003, according to the report, which logs quarter-by-quarter percentages of worldwide sales scored by each vendor.

So far this year F5 is slipping from the No. 2 spot it held at the end of last year, and Aventail is slipping from No. 3 to No. 4. The report does not include sales for the fourth quarter of 2006, so the jury is still out for end-of-year rankings.

Citrix had no SSL VPN offering at all until it bought Net 6. In 2005, its first year selling the former Net 6 gear, Citrix claimed the No. 5 spot, and so far this year has staked out No. 2, leapfrogging Aventail and Nortel.

Symantec, which was No. 5 before Citrix got into the game, has slipped in the Synergy rankings to No. 7 last year down to No. 8 so far this year, tied with SonicWall.

Cisco has jumped in at No. 6 so far this year, pushing down Array Networks to No. 7. Cisco has shown significant market share jumps over the first three quarters this year from 2.8% in the first quarter to 6.6% in the second to 11.2 in the third.

Tim Greene is senior editor at Network World.