The different licensing “levels” available on the Cisco Adaptive Security Appliances allow an organization to buy only what they need while retaining the option to upgrade in the future, if necessary.
For example, a small business with 15 employees may start out with a Cisco ASA 5505 with a 25-user (or, more correctly, 25-host) license. As new employees are hired — or existing employees begin using Wi-Fi on more devices — they may approach the limit and find it necessary to upgrade to a 50- or unlimited-user license.
Once you have obtained a new “activation key”, the process of upgrading the license on a Cisco ASA is among one of the simplest tasks you can perform, although it often times will require a reload of the device to take effect.
You can see what license you currently have installed using the show activation-key command:
Upgrading to our new license is simply a matter of going into global configuration mode and using the activation-key command to provide the new license key to the ASA:
Our new activation key was accepted. The above output shows that the activation key saved in flash memory is “Restricted” while the new one we’ve just supplied is “Unrestricted”. The ASA asks us to confirm that we want to update the key? Go ahead and press ENTER.
The Cisco ASA series tells us that the activation key stored in flash was updated (and will take effect upon the next reload), but the running activation key was not changed. When you see this, the ASA is telling you that you need to perform a reload for the new features to take effect.
I’ll go ahead and do that, though you might need to wait for a maintenance window or planned downtime.
Once the ASA has reloaded, we can log back in and verify that our new license — and new features — are active:
The ASA is back up and running and you can start using the additional features that your new license provides.
More How-to: How to Configure Cisco ASA 5505?