SearchNetworking has just published my article describing the issues you’ll face when deploying virtualized firewalls (you might want to read the one describing benefits and drawbacks of virtual appliances first). The article focuses primarily on the VMsafe Network API (aka dvFilter) and VMware’s vShield; you’ll find more in-depth information on alternate solutions (including HP’s and Juniper’s products using dvFilter API and Cisco’s vPath API) in my VMware Networking Deep Dive webinar (register here or buy a recording).
Ivan Pepelnjak, CCIE#1354, is the chief technology advisor for NIL Data Communications. He has been designing and implementing large-scale data communications networks as well as teaching and writing books about advanced technologies since 1990. See his full profile, contact him or follow @ioshints on Twitter.