The PIX uses software licensing to enable or disable features within the PIX OS. Although the hardware is common to all platforms (except that certain licenses can ship with additional memory or hardware accelerators) and the software is common, features differ depending on the activation key.

The activation key allows you to upgrade features without acquiring new software, although the process is similar. The activation key is computed by Cisco depending on what you have ordered and your serial number; it is different for each piece of PIX hardware. The serial number is based on the flash, so if you replace the flash, you have to replace the activation key.

The activation key enables feature-specific information such as interfaces, high availability, and type of encryption. More specific information is found in the section, PIX Licensing and Upgrades.

To get information about the activation key, use the show version command. The command provides information about the code version, hardware information, and activation key information. Alternately, the command show activation-key provides this printout:

PIX1# <b class="bold">show activation-key</b> Serial Number:  808413563 Running Activation Key: 0xf9200218 0x4c8b6b1f 0x253632cd 0x8c5d666b Licensed features for this platform: Maximum Physical Interfaces : 10 Maximum VLANs                : 100 Inside Hosts                 : Unlimited Failover        ...