hi,
per my notes:
In pure Cisco terms, a virtual firewall is called a Security Context. You might think of this Security Context as its own firewall within the Cisco ASA. You can define your own security policy for this virtual firewall. It can possess its own interfaces or even share interfaces with other virtual firewalls (with the exception of transparent mode virtual firewalls). It can even feature its own administrative user accounts. In fact, for those responsible for the device, it will appear to be a fully functional standalone device, and they can even be completely unaware of the fact that it is truly a firewall within another firewall.
As you might expect, to have a Cisco ASA engage in this rather remarkable capability, you must convert the operational mode of the device. Thus, an important first step in the configuration is converting the device to what is termed "multiple mode."
Once the device is in the correct mode to support virtualization, the job of the administrator is to create the required Security Context and assign the required resources. The administrator can also configure important resource limits for the various contexts to ensure the overall Cisco ASA does not have its performance degraded due to resource oversubscription. Finally, the Cisco ASA administrator must configure each context with the required IP addressing and access controls appropriate for each virtual device.
