How Link Control Monitor and Heartbeat works in HA configuration

This article explains how the link monitor and heartbeat for HA work, and what happens if this link goes down.

CAUTION: HA does not support PortShield interfaces.

EXAMPLE: Configuration Example

• The LAN (X0) interfaces are connected to a switch on the LAN network. The WAN (X1) interfaces are connected to another switch, which connects to the Internet.
• The dedicated HA interfaces are connected directly to each other using a crossover cable on X6 interface.

Monitor link could be either physically or logically down.

1st phase : the link control monitor is UP, all heartbeat are send through him.

Log Alert Message on the primary Firewall : 

   NOTE:  X0 should be configured, then the SonicWall will only use X0 to transmit the heartbeat.

Log message on Primary SonicWall :

Now all heartbeats are sent through X0, but X6 heartbeat stills sends in case the link becomes active.

TIP: If the Monitor Link is down, no status change are made.

NOTE: If both links (X0 and Monitor) are down, both firewall change their status in Active. When one of the link is back, the primary will preempt the active role, also if before the secondary was active and preempt isn't enable.