[ascen]

Thanks GP, for making me take yet another look at it.

I was testing it from my laptop on the same local network,
so the external IP was never an issue.
The actual problem was that the server was running an unpatched version, and Dom3 displays this situation as not having found a server at all.

Once I patched the server and tried again, it works like a charm.
So the displayed IP has no function at all - even though it lists a loopback address, it's still listening on the local network address(es).