Cisco ASA 5505 - Manual (Page 1307)

C H A P T E R
62-1
Cisco ASA 5500 Series Configuration Guide using the CLI
62
Configuring Active/Standby Failover
This chapter describes how to configure Active/Standby failover and includes the following sections:
• Information About Active/Standby Failover, page 62-1
• Licensing Requirements for Active/Standby Failover, page 62-6
• Prerequisites for Active/Standby Failover, page 62-6
• Guidelines and Limitations, page 62-6
• Configuring Active/Standby Failover, page 62-7
• Controlling Failover, page 62-16
• Monitoring Active/Standby Failover, page 62-18
• Feature History for Active/Standby Failover, page 62-18
Information About Active/Standby Failover
This section describes Active/Standby failover and includes the following topics:
• Active/Standby Failover Overview, page 62-1
• Primary/Secondary Status and Active/Standby Status, page 62-2
• Device Initialization and Configuration Synchronization, page 62-2
• Command Replication, page 62-3
• Failover Triggers, page 62-4
• Failover Actions, page 62-4
Active/Standby Failover Overview
Active/Standby failover enables you to use a standby ASA to take over the functionality of a failed unit.
When the active unit fails, it changes to the standby state while the standby unit changes to the active
state. The unit that becomes active assumes the IP addresses (or, for transparent firewall, the
management IP address) and MAC addresses of the failed unit and begins passing traffic. The unit that
is now in standby state takes over the standby IP addresses and MAC addresses. Because network
devices see no change in the MAC to IP address pairing, no ARP entries change or time out anywhere
on the network.