The director of analyst firm, Hydrasight Pty Ltd., Michael Warrilow, said it is likely IronPort has been an acquisition target for a number of vendors.

"Cisco is paying a premium for a high-performance solution which suggests that other vendors such as Symantec Corp., may have been knocking on IronPort's door," Warrilow said.

He believes the acquisition, which is expected to close mid-year, will interrupt the partnership Cisco has already established with Microsoft Corp.

This means Microsoft users will be impacted, Warrilow added.

Last year both vendors announced a number of joint partnerships around policy enforcement and access control interoperability including the Network Access Protection (NAP) initiative.