by Darius Kazemi, December 6 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.

Telnet changes

RFC-340 is titled “Proposed Telnet Changes”. It's authored by Tom O'Sullivan of Raytheon and dated May 15, 1972.

The technical content

This is a reply to Jon Postel's RFC-328, which proposed three changes to Telnet. The author agrees with Postel's first suggestion, which is to get rid of the minimum Telnet implementation.

He disagrees with Postel's two other proposals: that Data Types and Hide Your Input be dropped.

His objection to the removal of Data Types is based on the need to switch to binary data stream representations for certain applications via Telnet, and that contrary to Postel's claim that there is no way to switch back to Telnet ASCII, you could simply switch back using a code that is not present in the Telnet spec and that would be okay.

His objection to the removal of Hide Your Input is that just because something is difficult to implement doesn't mean it should not be implemented. In particular, protecting passwords is important and is worth the difficulty in navigating solutions.


This comes in just under the wire, on the literal due date of May 15 that Postel set for accepting feedback before assuming it would pass consensus by default.

How to follow this blog

You can subscribe to this blog's RSS feed or if you're on a federated ActivityPub social network like Mastodon or Pleroma you can search for the user “@365-rfcs@write.as” and follow it there.

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.