|By default, Telnet servers listen on TCP port 23.|
You have to configure the server and all firewalls and proxies.
Also depends on the client. Some can use telnet ip address port instead of ip address:port. host /PORT=80 and others.
See man telnet or use telnet --help or your help system.
I read it wrong and answer it wrong too. So get off my case you peanut.