[OpenIndiana-discuss] Heads up OpenSSH config change

[Marcel Telka]

On Tue, Oct 15, 2024 at 10:29:54AM +0200, Till Wegmüller wrote:
> Hello everyone.
> 
> We have recently packaged OpenSSH 9.9 and have found that this also requires
> us to distribute a configuration change. If you have not edited your SSH
> Config this will not effect you. If you have edited your sshd_config you
> will need to run the following sed script before you run pkg update.
> 
> sed -i "s/ListenAddress ::/#ListenAddress ::/g" /etc/ssh/sshd_config
> 
> Alternatively make sure that all ListenAddress directives are either
> Uncommented or commented out.
> 
> The reason for this config change is, that we had a differing behaviour on
> our OS for how ListenAdress works compared to what you find on the internet.

This different behavior was because of this patch:
0020-Compatibility-fix-for-ListenAddress.patch

Since it got removed with the OpenSSH update to 9.9p1[1] then the
ListenAdress behavior changed and is now aligned with the upstream
OpenSSH.

[1] https://github.com/OpenIndiana/oi-userland/pull/19011

> We do not know what introduced this behaviour in the past but it seems to
> have been fixed upstream. We thus make sure OpenSSH behaves as people expect
> it to when changing the config.

The explanation for different ListenAdress behavior is directly in the
patch that got removed:

In SunSSH, a config that specifies only "ListenAddress ::" in
fact will listen on both IPv4 and IPv6.

So in short, it was so for historical reasons.

-- 
+-------------------------------------------+
| Marcel Telka   e-mail:   marcel at telka.sk  |
|                homepage: http://telka.sk/ |
+-------------------------------------------+