It might be required that due to IP address shortage or IP address overlap in the Internal Network , we might need to change the Fail-over interface IP addresses.
For ex:- We see this error on the ASA device while trying to configure the ASA device and the Fail-over IP are overlapping.
WARNING: 192.168.0.0-192.168.255.255 overlaps with failover interface address. The failover units may become active
This is the Fail-over configuration causing this error:-
failover lan unit primary
failover lan interface FAIL GigabitEthernet0/5
failover link STATE GigabitEthernet0/4
failover interface ip FAIL 192.168.201.1 255.255.255.252 standby 192.168.201.2
failover interface ip STATE 192.168.202.1 255.255.255.252 standby 192.168.202.2
To change the IP address on the Fail-over interface , we need to follow these steps:-
1) Disable the Fail-over in the Primary unit:-
2) Fail-over status on the Secondary Unit will go to:-
Failover Off (pseudo-Standby) Failover unit Secondary
3) Change the IP address on both the ASA units separately. It will be the same command on both the units:-
failover interface ip FAIL 172.16.2.3 255.255.255.252 standby 172.16.2.4 failover interface ip STATE 172.16.4.5 255.255.255.252 standby 172.16.4.6
4) Once , you configure the IP address information , re-enable the fail-over first on the Primary unit and then on the Secondary Unit.
5) Fail-over will come up fine with the changed IP address on the Fail-over interface.
If you have a switch connected between the ASA Units for the Fail-over interfaces , I would suggest clearing the ARP entries on the switch.