You are investigating issues with to gateway cluster members are not able to establish the...

The FWD daemon uses TCP port 256 to do a Full Synchronization between gateway cluster members. This port is also used for other synchronization types, such as Delta Synchronization and Accelerated Synchronization. The FWD daemon is responsible for synchronizing the connections table, NAT table, and VPN keys between cluster members. References: ClusterXL Administration Guide, SK25977 - Ports Used by Check Point Software