In a FortiGate active-active HA deployment in Azure, synchronization between instances is achieved using:

FortiGate Clustering Protocol (FGCP) – This is the primary protocol used to synchronize configuration and session information between HA peers.

Heartbeat interfaces – These interfaces are specifically configured to exchange HA state and sync data between the FortiGate VMs, ensuring cluster consistency.

The FortiGate VM and the Windows Server VM are in different subnets but within the same Production virtual network, which means they can communicate by default unless restricted. Azure allows ICMP between subnets, but Windows VMs have ICMP blocked by default in their firewall settings. Therefore, the likely reason for the ping failure is that the Windows Server’s firewall is blocking ICMP (ping) traffic.

Azure Route Server enables dynamic route exchange using BGP between your Azure virtual network and network virtual appliances (NVAs) or on-premises networks. It provides a centralized and scalable solution for route management, allowing seamless integration of routing updates without manual configuration changes.