Windows Enable Telnet -

Or, for the truly old-school:

For years, Microsoft shipped Telnet enabled out of the box. But as the internet grew wilder and hackers learned to sniff plaintext passwords off the wire (yes, Telnet sends everything—including login credentials—in clear text), Redmond made a wise choice. Starting with Windows Vista, the Telnet client became an optional feature , disabled by default. The server side? Removed entirely after Windows XP. windows enable telnet