1. Your first step is to purchase the Licence you require from an authorised cisco reseller.
2. When your licence arrives you need to locate the PAK that is on the certificate.
3. You need the Serial number of the ASA 5500, to get this either look on the chassis of the device or issue a “show version” command.
5. Check the PAK details, and add more as required > Click “All Done”.
6. Enter the Serial Number of the ASA and tick “I Agree..” > Enter/Check your details > Enter the Licensee details (If Different) > Continue.
7. Read the Summary > Submit > Wait for it to stop saying “Processing” > When complete it should “Go Green” and say Registration Complete.
10. When the Licence comes in, the detail that you need is the activation key, it will look like : dd12eb50 9e16d5bb 45b2a92c 78901838 44999999
11. You add this licence to the ASA with an “activation-key” command.
To add a Licence from the ASDM
1. Connect via ASDM.
2. Navigate to > Configuration > Device Management > Licensing > Activation Key > Paste in the new activation key > Update Activation Key.