Telnet on Cygwin
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
If you got the response above, BINGO! We found your problem and is very easy to solve. Open the cygwin setup and install the inetutils package - it is under category Net. Check if the installation was successful with the commands below (of course you might get a different telnet version).
$ which telnet /usr/bin/telnet $ telnet --v telnet (GNU inetutils) 1.5
If your system is still using the Microsoft telnet, check your Cygwin session's PATH variable and make sure that the location of the Cygwin telnet comes before the windows one.