The secure tunnel is used by Unitrends to create an optimized, secure, encrypted tunnel for multiple Unitrends systems. The secure tunnel offers a scalable solution for enabling multiple clients to connect to a single server process through a single UDP port.
There are two typical cases for using the secure tunnel with Unitrends systems. The first is a replication scenario where there is a target system and one or more source backup systems. In this case, the secure tunnel is configured between the target and the source systems in order to facilitate both the replication of data and the management of the systems. The second is the case where two or more systems are managed by a designated management system. With this setup, you can then perform operations for all systems from one Unitrends system interface.
The primary advantages of the secure tunnel are that it enables radically simpler firewall management (since only one port is needed between off-premise Unitrends systems) and that it enables much higher session availability because it can handle lower quality WAN lines that would typically result in session termination (through UDP-level ride-through of short-lived transient line failures).