San Jose-based Cisco said today that it is acquiring San Bruno-based IronPort, a maker of security appliances, in a deal worth $830M in cash and stock. IronPort develops security products targeted at spam and spyware filtering. IronPort will become part of Cisco's Security Technology Group. The acquisition is expected to close in the third quarter of Cisco's fiscal 2007 year. IronPort employs 408 in San Bruno.