Using telnet in Cygwin is very easy, but most people does not realize that it is not installed by default, therefore when you try to run telnet on a Cygwin shell you are instantly returned to the prompt. This happens because Cygwin finds the Microsoft telnet installed in your windows box and runs it; but this won't work in a Cygwin shell. To find out if this is the source of your problems type:

    $ which telnet
    /cygdrive/c/WINDOWS/system32/telnet