Network access control start-up Lockdown Networks has shut down operations, becoming another in what has become a string of vendors floundering in the network access arena.

The company blamed its failure on economic trends and slower than predicted adoption of NAC. As a result of these problems, the company was unable to raise the venture capital it needed to continue. It had raised more than $14 million last fall from Ignition Partners, Intel Capital, Integral Capital Partners and Cargill.

On its Web site the company said: "Lockdown Networks today announced that it is ceasing operations effective March 18, 2008. Due to overall economic trends and slower than predicted adoption of Network Access Control (NAC) technology, the company was unable to raise additional sufficient venture capital to continue. Lockdown is contacting customers and partners directly to provide more information. Certain employees have been retained to oversee the shutdown of the company and entertain offers to Lockdown's intellectual property."

Another NAC vendor, Bradford Networks, says it will buy back Lockdown gear in exchange for purchase of Bradford gear. Details of the offer were unavailable immediately. (Compare NAC products.)

Other vendors have had trouble making headway with NAC. Caymas Systems shut down last year, selling its NAC assets to Citrix.

The NAC company Vernier Networks has changed its name to Autonomic Networks, refinanced and is cooking up new technology that it says will complement its current Edgewall NAC appliances.