"When you also consider Cisco's focus on unified communications, it will be interesting to watch what this means for Microsoft - particularly given the joint partnership on securing the enterprise network via initiatives such as NAC and NAP interoperability," Warrilow said.

"This investment is evidence that Cisco wants a piece of the security market - this time in the e-mail and messaging arena." "When you consider the various

It is unknown at this stage how many of IronPort's existing 408 employees will be integrated within Cisco.

Tom Gillis, IronPort vice president of marketing, said it is likely all staff will be retained.

A Cisco spokesperson confirmed IronPort's Chief Executive Officer Scott Weiss will report directly to Cisco Vice President and General Manager of the VPN and security unit, Richard Palmer.