by Darius Kazemi, November 8 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.

Better Host-IMP error messages

RFC-312 is titled “Proposed Change in IMP-to-Host Protocol”. It's by Alex McKenzie of BBN and dated March 22, 1972.

The technical content

BBN wants to change around some of the existing error messages in the interface between the Host (Network Control Program) and the IMP, including adding some new error messages.

There is a kind of general “things are clogged up for an unspecified reason” error state that was mentioned in RFC-270. The author says that BBn would like to provide new error messages when this happens. Right now there's no error message during the state, just a bunch of NOPs (no-operation commands, basically filler commands that do nothing) that are sent to signal the error state.

They also propose specific error messages when messages are too short, too long, or an illegal message type.


Making more descriptive and varried error messages and types is, to my mind, always a good thing.

But this would require NCPs to be rewritten, which I imagine people won't be very happy about. It seems like the kind of thing people would propose wait until the next “major version” of a host-host protocol comes out and everyone has to rewrite their NCP anyway.

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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.