[thund]

wow, how to romanticize X.400 ...

- poor Internet fit, assuming managed, trusted networks - some promises depended on all participating systems behaving honestly

- once a message reaches another server, you cannot guarantee it isn't copied, backed up, or logged

- X.400 read receipts: more reliable but also more privacy invasive

- X.400 metadata: carries a lot of routing, classification, and organizational info leading to potential privacy leaks

- SMTP is ugly but observable, you don't need a standard specialist to debug issues

[grandinj]

Yeah, as someone who had to implement a protocol stack to talk to a X.400 server, it was not fun at all. Weird encodings, monster spec, all sorts of weird server-specific stuff that you had to do exactly right if you wanted the server to accept your email.

Compared to that, when I implemented RFC821/822 (i.e. SMTP) mail, the hardest part was the weird line-encodings, but other than that, the spec was ___so___ nicely readable and pragmatic.

[bigfatkitten]

For the use cases where it found adoption, such as in air traffic management, formal military messaging, diplomatic cables etc, these are all mostly desirable properties.