Virtual Firewalls

This section introduces the concepts and terminology:

• Many levels of firewall statefulness
• Differences between virtual firewalls and contexts on physical firewalls;
• Virtual firewall taxonomy (from appliances to VM NIC firewalls)

Numerous virtual firewalls are nothing more than traditional firewalling software running within a virtual machine. This section describes the benefits and drawbacks of moving from physical appliances to virtual firewall appliances.

VM NIC firewalls are solutions that filter traffic between a virtual machine and adjacent virtual switch. This section describes several VM NIC firewall implementation models and the tradeoffs they're making.

You could implement security functionality in virtualized environment with service insertion: redirecting the traffic through a security appliance (physical or virtual).