Cisco ASA - Multicast After Failover
Posted: 2024-07-18
After a failover event, Cisco ASA may randomly no longer pass multicast traffic.
Upon a failover event, Cisco ASA has done something I have never seen before.
If all of a sudden you find your ASA no longer passing multicast traffic after a failover event, check if the following has been added to your interfaces.
Show run Int Po10
...
no mfib forwarding
...
If it has, that means ASA has decided to add this configuration on the ASA. I have seen configurations being removed before that's not new, but added? That's actually pretty crazy.
Fix for affected interfaces:
Interface Po10
..
mfib forwarding
..
It will no longer appear in the configuration, and multicast traffic should be restored.