Which condition could cause a failover in a Citrix ADC high availability pair to not occur, keeping the secondary from becoming primary?

• A. HA monitoring is enabled on an interface of the secondary node that shows as ENABLED, DOWN
• B. HA monitoring is enabled on a disabled interface of the primary node
• C. HA heartbeats are only seen on some enabled interfaces of the secondary node
• D. The independent Network Configuration mode is enabled on the primary node

Answer: (A)

High availability depends on a working HA heartbeat path between the primary and secondary. If the interface used for HA monitoring on the secondary is configured as ENABLED but is actually DOWN, the secondary cannot receive or send HA heartbeats. Without reliable heartbeat communication, the secondary cannot detect that the primary has failed, so it cannot promote itself to primary. In other words, the essential signal that triggers failover is blocked by a down interface on the secondary, preventing the secondary from taking over.

The other scenarios are less definitive: if the primary’s HA interface is disabled, there may still be another path for heartbeat and failover could occur; if heartbeats appear only on some interfaces on the secondary, there might still be enough communication to trigger failover under some conditions; and enabling independent network configuration on the primary affects configuration syncing, not the fundamental failover trigger.