When I use telnet with rlwrap it looks like there is no way to kill the client. Am I missing something here or I really have to kill the process with the kill command?
rlwrap is a wrapper for GNU readline, so it's doing everything locally and only passing your input through after you press Enter. When you press Ctrl+] you don't see the
telnet> prompt because readline has not yet sent your input.
To kill your telnet connection, then, press Ctrl+], then q, then Enter.
Ctrl+c, Esc, Enter, Ctrl+], Enter, q, Enter