The following must be identical: Model (5505 or 5510 or 5520, etc) Amount of RAM Number of Interfaces (should be the same type as well) External Modules (CSC-SSM or IPS-SSM) Activation key with the same features Failover mode Encryption Level Number of VPN peers *** Same size Flash is not required **** Definitions: Active -> ResponsibelContinue reading “ASA Failover and Redundancy”