TCP targets (the only kind currently in Boundary) actually work with _any_ TCP connection. The `boundary connect <subcommand>` bits are just some CLI syntactic sugar around the main `boundary connect` command -- which works all by itself! -- that fill in IP/port and other information for various clients. (This has been an unfortunate bit of confusion for many people trying Boundary out. We'll take another look at how we can make this more obvious in our getting started/learn docs.)

It's all TCP though. Eventually we'll do more interesting things with specific protocol types.