What could cause failover not to work in a Citrix ADC HA pair?

• A. HA heartbeats are only seen on some enabled interfaces of the Secondary Node.
• B. HA monitoring is enabled on an interface of the Secondary Node that shows as ENABLED, DOWN.
• C. The Independent network configuration (INC) mode is enabled on the Primary Node.
• D. HA monitoring is enabled on a disabled interface of the Primary Node.

Answer: (B)

Failover relies on a working inter-node health path: heartbeats and health monitoring must be able to travel between the two ADCs. If HA monitoring is enabled on an interface of the Secondary Node that shows as ENABLED, DOWN, there is no active link for those checks. The monitoring traffic can’t reach the Primary, and the Primary can’t reliably determine the health of the Secondary or trigger failover. In short, a monitoring path on a down interface breaks the interconnect used for HA, preventing failover from functioning correctly. Ensure the interconnect interface used for HA is up and that monitoring is enabled only on interfaces that are truly UP.