by Darius Kazemi, July 25 2019

In 2019 I'm reading one RFC a day in chronological order starting from the very first one. More on this project here. There is a table of contents for all my RFC posts.

A Telnet client

RFC-206 (PDF) is titled “A User TELNET: Description of an Initial Implementation”. It's by Jim White of UCSB and dated August 9, 1971.

The technical content

This document describes the implementation of a Telnet client at UCSB. (The phrase White uses is “user Telnet” but that is in opposition to what we'd call a “server Telnet”; the phrase we'd use to today is “client”.) I'm not going to get into the nitty-gritty because it's a pretty straightforward, if partial, implementation of the RFC-158 Telnet. Still, there is some interesting information in here.

The author notes that the users of the Culler-Friend On-Line System at UCSB do not have access to the ARPANET by default. This privilege must be earned, or at least requested. They need to contact their Computer Center liaison to get special access first.

When a user connects to Telnet at OLS, the user is asked for a remote site number, and then for a remote socket number, at which point a connection is attempted.

The document contains a list of 21 ARPANET sites and their site numbers, for reference. The default socket you connect to for Telnet is 1, but you have the option to connect to a different socket if you have a special need.

Most of the rest of the document discusses the peculiarities of character encoding and the virtual teletype system used by this Telnet client.

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About me

I'm Darius Kazemi. I'm an independent technologist and artist. I do a lot of work on the decentralized web with ActivityPub, including a Node.js reference implementation, an RSS-to-ActivityPub converter, and a fork of Mastodon, called Hometown. You can support my work via my Patreon.