Comment # 8 on bug 1212627 from Adam Majer

(In reply to Jonathan Kang from comment #7)
> (In reply to Adam Majer from comment #6)
> > Created attachment 867859 [details]
> > fails after NetworkManager
> > 
> > With additional changes,
> > 
> > # /etc/systemd/system/sshd.service.d/01-after-network.conf
> > [Unit]
> > After=NetworkManager-wait-online.service
> > 
> > [Service]
> > Restart=always
> > RestartSec=5s
> > RestartPreventExitStatus=
> > 
> > SSHD comes up *most of the time* while still failing sometimes. That is,
> > Network Maanger signals via NetworkManager-wait-online.service that it is
> > complete, but the IP address is still not available for bind by SSHD. I've
> > attached a log that shows exactly this.
> 
> > sshd[1225]: error: Bind to port 22 on 2a01:4f8:c012:9cdf:0:aead:1:aead failed: Cannot assign requested address
> 
> sshd waits for an ipv6 address, is this intentional? In this logs you
> provided, when sshd starts, there is already an ipv4 address available. But
> there is no ipv6 address assigned yet.

The IPv4 address is non-routable and configured via DHCP, and the only public
address available is the IPv6. It's configured manually, so it's not like there
is a long wait for RA or something,


ipv6.method:                            manual
ipv6.dns:                              
2a01:4ff:ff00::add:1,2a01:4ff:ff00::add:2
ipv6.dns-search:                        --
ipv6.dns-options:                       --
ipv6.dns-priority:                      0
ipv6.addresses:                         2a01:4f8:c012:9cdf::1/64,
2a01:4f8:c012:9cdf:0:aead:1:aead/64


ipv4.method:                            auto
ipv4.dns:                               --
ipv4.dns-search:                        --
ipv4.dns-options:                       --
ipv4.dns-priority:                      0
ipv4.addresses:                         --


In the "old days", all network interfaces should be configured as much as
possible before the rest of the system is signaled that network is ready. So,
passive configuration via RA for IPv6 would be out-of-scope for this wait but
everything else should be blocking. Static IP assignments should definitely be
all assigned prior to signaling network setup is successful.

Basically, I would expect all configured network interfaces to be up and
configured completely before proceeding. It's not OR condition here but AND.
Optionally things could proceed after some timeout, like 2 or 3 minutes, if we
are waiting for external resources that may be failing (eg. DHCP)

Finally, an answer here that "it would work if you just listen on wildcard
address" is not really a good answer here.