Bug#1103773: openssh-server: systemd unit to After=network-online.target

Control: severity -1 wishlist

On Mon, Apr 21, 2025 at 02:49:14PM +0200, Chris Hofstaedtler wrote:
>* Martin-Éric Racine <[email protected]> [250421 14:42]:
>>The systemd unit current launches:
>>
>>After=network.target remote-fs.target nss-lookup.target
>>
>>This doesn't guarantee that we have acquired an IP address (see: https://www.freedesktop.org/wiki/Software/systemd/NetworkTarget/).
>>
>>Because of this, binding to an address using e.g. 'ListenAddress 192.168.1.12' will make sshd fail to launch if the interface hasn't acquired an IP yet.
>>
>>network-online.target should probably be added to the above to positively ensure that we've acquired an IP before sshd launches.
>
>network-online.target makes no guarantees on addresses, or even the 
>specific address configured in sshd.conf.

Yeah, I think the requested change would be counterproductive for other 
users: a lot of people want sshd enabled as soon as possible, and most 
people don't explicitly set ListenAddress.

>If it helps in your local setup, I'd encourage you to use a local 
>override file.

I'd be happy to add additional advice about this to README.Debian if 
somebody else writes it.  But ideally it'd be more fine-grained than 
just whacking in a dependency on network-online.target; perhaps we can 
advise people how to configure their system so that ssh.service waits 
for a particular interface to come up.

Thanks,