I figured out how to eliminate the "port" setting. You have to use "edit" and then erase it.
You cannot "set" it to empty, but you can "edit" it to empty. Go figure.
I had the same problem. I downloaded the current "Combined RouterOS package" and it had the routing-test in it. I guess the "routing-test" is omitted from some distributions.The routing-test package seems to be missing from the RB5xx packages, why, it's in the x86 packages?