By default, active interfaces that have failed and then repaired automatically return to become active interfaces in the group. This behavior is controlled by the setting of the FAILBACK parameter in the daemon's configuration file. However, even the insignificant disruption that occurs as data addresses are remapped to repaired interfaces might not be acceptable to some administrators. The administrators might prefer to allow an activated standby interface to continue as an active interface. IPMP allows administrators to override the default behavior to prevent an interface to automatically become active upon repair. These interfaces must be configured in the FAILBACK=no mode. For related procedures, see How to Configure the Behavior of the IPMP Daemon.
When an active interface in FAILBACK=no mode fails and is subsequently repaired, the IPMP daemon restores the IPMP configuration as follows:
The daemon retains the interface's INACTIVE status, provided that the IPMP group reflects the original configuration of active interfaces.
If the IPMP configuration at the moment of repair does not reflect the group's original configuration of active interfaces, then the repaired interface is redeployed as an active interface, notwithstanding the FAILBACK=no status.
The FAILBACK=NO mode is set for the whole IPMP group. It is not a per-interface tunable parameter.