Subject: bug#66667: [PATCH] Socket forwarding in emacsclient --tramp-prefix example

From: Michael Albinus <[email-masked]>
Date: Sat, 21 Oct 2023 18:57:59 +0200

Peter Oliver <[email-masked]> writes:

Hi Peter,

> Previously, the emacsclient --tramp-prefix documentation suggested
> using it in conjunction with a forwarded TCP port.  However, OpenSSH
> has supported forwarding sockets since version 6.7 (released 2014), so
> let’s suggest that instead.  Sockets require less manual configuration
> than ports, are less likely to clash, and are more secure, so will be
> a better choice for the majority of people looking to set up this
> facility for the first time.

Thanks for this. However, I don't believe we shall document this instead
of server ports. Better would be to document both variants. The reason
is, that sockets don't exists on every platform, see the "#ifdef
SOCKETS_IN_FILE_SYSTEM" directive in emacsclient.c.

Furthermore, people might run older sshd servers on remote systems,
which don't support socket forwarding. It must be also at least OpenSSH
6.7, like the client on the local side. Think about routers, NAS
systems, and alike, which aren't upgraded over years. As Tramp
maintainer I know what I'm speaking about.

The %TOKEN percent expansion (your %r and %i tokens) exists since
OpenSSH 8.2 only.

Best regards, Michael.