You obviously have not used any remote monitoring tools.
Just to pick one, look at kaseya. Unless everything on the network is locked down, it is going to find a way to connect to the server. Heck, by default it gives you a half dozen ways of remote viewing (mstsc, vnc,..) without manually installing anything beyond the small client package. It's very good software from a management perspective, but using it in a moderate size and diverse environment, it's border-line malicious.
"What I've done, of course, is total garbage." -- R. Willard, Pure Math 430a