Which interface is used by SonicOS as the backup heartbeat link?

In SonicWall's architecture, the backup heartbeat link is designed to provide a failover mechanism that ensures continuous connectivity in case of primary link failure. SonicOS utilizes this backup link for failover communication between the devices in a high availability (HA) setup.

The X3 interface, in particular, serves this function by allowing the devices to communicate their operational status and synchronize their configurations. This mechanism ensures that if the primary link fails, traffic can seamlessly continue to flow without significant disruption. The X1 and X2 interfaces typically handle primary data traffic, while the Y1 interface may not be designated specifically for heartbeat purposes, which makes X3 the correct interface for this role.

Understanding the purpose of the X3 interface in relation to high availability configurations provides crucial insights into maintaining network reliability and minimizing downtime.