Telnet

Telnet is the traditional protocol for making remote console connections over TCP. Telnet is not secure and is mainly used to connect to legacy equipment nowadays. Telnet traffic is easily sniffed for passwords and connections should never be made over any untrusted network including the Internet unless encrypted with SSH or tunneled though a VPN. For a secure alternative see SSH.

Installation

Install the inetutils package.

It includes a telnet client. A telnet server can be configured with systemd sockets or xinetd. telnetd via systemd requires only the inetutils package. To configure a telnet server with xinetd, install xinetd as well.

Configuration

To enable telnet server connections in systemd, enable telnet.socket (if the telnet server should be started on every boot), and start telnet.socket to test connectivity.

To enable telnet server connections in xinetd, edit /etc/xinetd.d/telnet, change disable = yes to disable = no and restart the xinetd service.

Enable systemd xinetd service if you wish to start it at boot time.

Testing the setup

Try opening a telnet connection to your server:

$ telnet localhost

Try a root login to see if your configuration permits it and the security implications that implies.

If the session disconnects before you receive a login prompt, try installing inetutils-git^AUR in place of the current inetutils and restarting telnet.socket.

Tip: If you receive junk codes from a remote telnet server sending non-ascii chars with a non-unicode encoding, you might want to try xorg-luit to solve this problem.