I have servers at our data center that I need to access from the development office. I also have servers at the development office that need to be accessible from the data center, though not quite as urgent. It would also be nice if, at some later point (should we grow), a second development office could be added to the mix, where everyone can see each other. Enabling this would allow any server or workstation to run a service that is listening for a remote connection from any location for things like file transfers, syncing mostly read-only databases, git pushes/pulls, etc.. It may not be the most professional, enterprise setup, but with a small, trusted development group and slow upload speeds at remote offices, it seems an easy and reliable way to keep everything up to date, including a live demo of our development efforts.
The data center, acting as host, has its network listed as advertised, client-to-client connections are on, Zentyal-toZentyal tunnels are on, and I've tried both settings for NAT. The client does not have any configuration that I can find for advertising a network. Once the tunnel is running, the two Zentyal servers could connect to anything on the remote LAN, without any hooks, but as for the other servers and workstations, they could only talk to their own LAN and addresses on the VPN (the remote and local Zentyal servers). I can only see a limited use for this configuration, and I cannot imagine that this was the intended purpose of a Zentyal-to-Zentyal VPN.
I was expecting to run a standard VPN server on both Zentyal machines and making each of them a client for the other VPN. I think I even untarred a standard Linux client bundle on the office router, without it being noticed by Zentyal's OpenVPN. Seeing an option for a Zentyal-to-Zentyal tunnel, my expectation is it would make the two networks operate like connected peers (i.e. automatically route/NAT traffic between them).