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Cisco ASA 5500 Series Configuration Guide using the CLI
Chapter3 Managing Feature Licenses
Information About Feature Licenses
Failover Licenses (8.3(1) and Later)
With some exceptions, failover units do not require the same license on each unit. For earlier versions,
see the licensing document for your version.
This section includes the following topics:
•Failover License Requirements and Exceptions, page3-28
•How Failover Licenses Combine, page3-28
•Loss of Communication Between Failover Units, page3-29
•Upgrading Failover Pairs, page3-30

Failover License Requirements and Exceptions

Failover units do not require the same license on each unit.
Older versions of ASA software required that the licenses match on each unit. Starting with Version
8.3(1), you no longer need to install identical licenses. Typically, you buy a license only for the primary
unit; for Active/Standby failover, the secondary unit inherits the primary license when it becomes active.
If you have licenses on both units, they combine into a single running failover cluster license.
The exceptions to this rule include:
•Security Plus license for the ASA 5505, 5510, and 5512-X—The Base license does not support
failover, so you cannot enable failover on a standby unit that only has the Base license.
•IPS module license for the ASA 5500-X—You must purchase an IPS module license for each unit,
just as you would need to purchase a hardware module for each unit for other models.
•Encryption license—Both units must have the same encryption license.
Note A valid permanent key is required; in rare instances, your authentication key can be removed. If your
key consists of all 0’s, then you need to reinstall a valid authentication key before failover can be
enabled.

How Failover Licenses Combine

For failover pairs, the licenses on each unit are combined into a single running failover cluster license.
For Active/Active failover, the license usage of the two units combined cannot exceed the failover cluster
license.
If you buy separate licenses for the primary and secondary unit, then the combined license uses the
following rules:
•For licenses that have numerical tiers, such as the number of sessions, the values from both the
primary and secondary licenses are combined up to the platform limit. If both licenses in use are
time-based, then the licenses count down simultaneously.
For example:
–
You have two ASAs with 10 AnyConnect Premium sessions installed on each; the licenses will
be combined for a total of 20 AnyConnect Premium sessions.
–
You have two ASA 5520s with 500 AnyConnect Premium sessions each; because the platform
limit is 750, the combined license allows 750 AnyConnect Premium sessions.