Cisco ASA Series Cli Configuration Manual page 356

Failover Times
If an interface has only IPv6 addresses configured on it, then the ASA uses IPv6 neighbor discovery
instead of ARP to perform the health monitoring tests. For the broadcast ping test, the ASA uses the IPv6
all nodes address (FE02::1).
If all network tests fail for an interface, but this interface on the other unit continues to successfully pass
traffic, then the interface is considered to be failed. If the threshold for failed interfaces is met, then a
failover occurs. If the other unit interface also fails all the network tests, then both interfaces go into the
"Unknown" state and do not count towards the failover limit.
An interface becomes operational again if it receives any traffic. A failed ASA returns to standby mode
if the interface failure threshold is no longer met.
Note
If a failed unit does not recover and you believe it should not be failed, you can reset the state by entering
the failover reset command. If the failover condition persists, however, the unit will fail again.
Failover Times
Table 1-2
Table 1-2 Cisco ASA 5500 Series ASA Failover Times
Failover Condition
Active unit loses power or stops normal operation.
Active unit main board interface link down.
Active unit 4GE module interface link down.
Active unit IPS or CSC module fails.
Active unit interface up, but connection problem
causes interface testing.
Failover Messages
When a failover occurs, both ASAs send out system messages. This section includes the following
topics:
•
•
•
Failover System Messages
The ASA issues a number of system messages related to failover at priority level 2, which indicates a
critical condition. To view these messages, see the syslog messages guide guide. To enable logging, see
Chapter 1, "Configuring Logging."
Cisco ASA Series CLI Configuration Guide
1-20
shows the minimum, default, and maximum failover times.
Failover System Messages, page 1-20
Debug Messages, page 1-21
SNMP, page 1-21
Minimum Default
800 milliseconds 15 seconds
500 milliseconds 5 seconds
2 seconds 5 seconds
2 seconds 2 seconds
5 seconds 25 seconds
Chapter 1 Information About Failover
Maximum
45 seconds
15 seconds
15 seconds
2 seconds
75 seconds