Re: /etc/services losses

[Taylor R Campbell <campbell+netbsd-tech-userlevel%mumble.net@localhost>]

> Date: Thu, 3 Aug 2023 12:41:53 +0200
> From: Hauke Fath <hauke%Espresso.Rhein-Neckar.DE@localhost>
> 
> IANA appears to have settled on submissions for port 465 (which, 
> coincidentally, was assigned to 'urd' in the netbsd-5 version, and the 
> NetBSD addition then declared the smtps alias). A web search for 
> 'smtps' confirms widespread use, so this should be maintained as an 
> alias for 'submissions' IMO.

`smtp(s)' and `submission(s)' are subtly different protocols and
should not be aliases:

- smtp(s) is for MTA<->MTA exchange of fully formed internet mail
  messages with complete headers.

- submission(s) is for an MUA to submit new messages, which may not
  have complete headers or fully qualified addresses or otherwise be
  fully formed, via a mail submission agent into the internet mail
  system.

I'm not sure if there is any port number that can rightly be called
`smtps' today.  I'm also not sure it matters if a TLS session is
preceded by the ten bytes `STARTTLS\r\n' on the wire or not.