ConSentry Networks is the latest network access control (NAC) vendor to bite the dust. The Milpitas, Calif.-based company, which lately had shifted its focus to making LAN switches and controllers, closed its doors last Thursday, according to Network World, which broke the story. No one at ConSentry answered the telephone on Tuesday, and an email went unreturned. Earlier this year, Trustwave acquired Mirage Networks, and in March 2008, prominent NAC player Lockdown Networks went out of business. Experts said pure-play NAC providers have had trouble competing against bigger companies. -- DK