If you need to check on the status of CARP, navigate to Status | CARP (failover). You will notice that there are two buttons on this page that can prove useful. Temporarily Disable CARP will, as the name implies, disables CARP on the firewall by removing the CARP virtual IPs. If the firewall was designated as MASTER before this function was invoked, then temporarily disabling CARP should cause the secondary firewall to become MASTER. This function, however, will not survive a reboot, and if you reboot the primary firewall, it will revert to being MASTER. CARP will also become re-enabled if you press the Enable CARP button.

If you need to keep CARP disabled through a reboot, you can click on the Enter Persistent CARP Maintenance Mode button. Invoking this functionality will disable CARP, and CARP being disabled will survive a reboot. In fact, CARP won’t become re-enabled until you click on the Leave Persistent CARP Maintenance Mode button.

If you are trying to diagnose a CARP issue, you may want to navigate to Status | System Logs, especially right after attempting synchronization. Recent log activity will document the attempted synchronization and might provide a clue as to what went wrong.