Name

telnet — stdin  stdout  - file  -- opt  --help  --version

Synopsis

telnet [options] host [port]

The telnet program logs you into a remote machine where you already have an account.

➜ telnet remote.example.com

Avoid telnet for remote logins: most implementations are not secure and send your password over the network in plain text for anyone to steal. Use ssh instead, which protects your password and data via encryption. There are two exceptions:

  • In a Kerberos environment, using secure (“kerberized”) telnet software on both the client and server side. See http://web.mit.edu/kerberos/ for more information.

  • Connecting to a remote port when you aren’t sending any sensitive information at all. For example, to check for the presence of a web server (port 80) on a remote system:

    ➜ telnet remote.example.com 80
Trying 192.168.55.21...
Connected to remote.example.com
Escape character is '^]'.
xxx               Type some junk and press Enter
<HTML><HEAD>      Yep, it’s a web server
<TITLE>400 Bad Request</TITLE>
</HEAD><BODY>
<H1>Bad Request</H1>
Your browser sent a request that
this server could not understand.<P>
</BODY></HTML>
Connection closed by foreign host.

    Note that you are simply connecting to the port, not necessarily using it in a correct or meaningful way.

To discourage you further from using telnet non-securely, we aren’t even going to describe its options.

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