I was both sad and excited to see that Apple removed telnet from Mac OS High Sierra, excited because telnet is a nearly 40 year old protocol that is highly insecure for network management and saddened because I often have to use telnet when at client sites.

Homebrew Telnet

There are a few different methods you can use to bring back telnet, including copying over the binaries from a Sierra install to /usr/local/bin (as seen here) or using a session manager like SecureCRT, but since I’ve been using Homebrew to manage a few other packages for a while now I figured I’d just go ahead and use that.

Homebrew Putty

A telnet client for the DS. It is a user command and a TCP/IP protocol used to access remote computers. Telnet is an old network communications protocol but one that often features in embedded hardware (although SSH has now taken over for the better stuff).

• If you use homebrew, BSD telnet is prepackaged and installable via brew install telnet. Improve this answer. Follow answered Sep 26 '17 at 6:50. 1,848 2 2 gold badges 6 6 silver badges 14 14 bronze badges. There are some issues going on.
• Homebrew’s package index. Implementation of Telnet and SSH.

• First install Homebrew from your terminal (warning: please don’t copy and paste code snippets from a web browser straight into your terminal, please double check your sources)
• Run

Homebrew Telnet Install

Homebrew Telnet Commands

There you have it. Run telnet by simply issuing the telnet command and the ip/port you want to connect to.