This paper discusses the possibility/feasibility of running a Linux Firewall as a Virtual Machine inside your XEN/KVM/VMware Hypervisor. The advantages and disadvantages are identified; and a solution is proposed on how you can actually achieve this. The paper is available in HTML and PDF versions.

… There is nothing much you can do “different”, with the so-called hardware/proprietary firewalls, compared to what you can do with Linux based firewalls. …