Bug#1111791: systemd: network-online.target reached before IPv6 address is ready

[Marcelo Gondim]

Package: systemd
Version: 257.7-1
Severity: important
Tags: ipv6
X-Debbugs-Cc: gondim at gmail.com




-- Package-specific info:

-- System Information:
Debian Release: 13.0
   APT prefers stable-updates
   APT policy: (500, 'stable-updates'), (500, 'stable-security'), (500, 
'stable')
Architecture: amd64 (x86_64)

Kernel: Linux 6.12.41+deb13-amd64 (SMP w/2 CPU threads; PREEMPT)
Locale: LANG=pt_BR.UTF-8, LC_CTYPE=pt_BR.UTF-8 (charmap=UTF-8), 
LANGUAGE=pt_BR.UTF-8:pt:en
Shell: /bin/sh linked to /usr/bin/dash
Init: systemd (via /run/systemd/system)

Versions of packages systemd depends on:
ii  libacl1            2.3.2-2+b1
ii  libapparmor1       4.1.0-1
ii  libc6              2.41-12
ii  libmount1          2.41-5
ii  libpam0g           1.7.0-5
ii  libseccomp2        2.6.0-2
ii  libselinux1        3.8.1-1
ii  libssl3t64         3.5.1-1
ii  libsystemd-shared  257.7-1
ii  libsystemd0        257.7-1
ii  mount              2.41-5

Versions of packages systemd recommends:
ii  chrony [time-daemon]            4.6.1-3
ii  dbus [default-dbus-system-bus]  1.16.2-2
ii  linux-sysctl-defaults           4.12
ii  systemd-cryptsetup              257.7-1

Versions of packages systemd suggests:
pn  libtss2-tcti-device0  <none>
pn  polkitd               <none>
pn  systemd-boot          <none>
pn  systemd-container     <none>
pn  systemd-homed         <none>
pn  systemd-repart        <none>
pn  systemd-resolved      <none>
pn  systemd-userdbd       <none>

Versions of packages systemd is related to:
ii  dbus-user-session  1.16.2-2
pn  dracut             <none>
ii  initramfs-tools    0.148.3
ii  libnss-systemd     257.7-1
ii  libpam-systemd     257.7-1
ii  udev               257.7-1

-- no debconf information

After upgrading some Debian servers from Bookworm to Trixie, during 
system reboot sometimes services start and sometimes they do not, 
because IPv6 is not yet configured on the network interface. IPv6 is 
statically configured in /etc/network/interfaces. Below are some logs 
where I noticed the issue with nsd and unbound:

2025-08-18T19:33:10.183996-03:00 DNS-AUTORITATIVO-02-STZ nsd[959]: nsd 
starting (NSD 4.12.0)
2025-08-18T19:33:10.184105-03:00 DNS-AUTORITATIVO-02-STZ nsd[959]: can't 
bind udp socket 2804:XXXX:40:0:187:XXXX:159:11 at 53: Cannot assign 
requested address
2025-08-18T19:33:10.184142-03:00 DNS-AUTORITATIVO-02-STZ nsd[959]: 
server initialization failed, nsd could not be started
2025-08-18T19:33:10.196883-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Main process exited, code=exited, status=1/FAILURE
2025-08-18T19:33:10.197009-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Failed with result 'exit-code'.
2025-08-18T19:33:10.197203-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
Failed to start nsd.service - Name Server Daemon.
2025-08-18T19:33:10.416114-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Scheduled restart job, restart counter is at 1.
2025-08-18T19:33:10.418873-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
Starting nsd.service - Name Server Daemon...
2025-08-18T19:33:10.484148-03:00 DNS-AUTORITATIVO-02-STZ nsd[1003]: nsd 
starting (NSD 4.12.0)
2025-08-18T19:33:10.484243-03:00 DNS-AUTORITATIVO-02-STZ nsd[1003]: 
can't bind udp socket 2804:XXXX:40:0:187:XXXX:159:11 at 53: Cannot assign 
requested address
2025-08-18T19:33:10.484276-03:00 DNS-AUTORITATIVO-02-STZ nsd[1003]: 
server initialization failed, nsd could not be started
2025-08-18T19:33:10.485385-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Main process exited, code=exited, status=1/FAILURE
2025-08-18T19:33:10.485464-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Failed with result 'exit-code'.
2025-08-18T19:33:10.485691-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
Failed to start nsd.service - Name Server Daemon.
2025-08-18T19:33:10.836173-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Scheduled restart job, restart counter is at 2.
2025-08-18T19:33:10.837853-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
Starting nsd.service - Name Server Daemon...
2025-08-18T19:33:10.901042-03:00 DNS-AUTORITATIVO-02-STZ nsd[1008]: nsd 
starting (NSD 4.12.0)
2025-08-18T19:33:10.901138-03:00 DNS-AUTORITATIVO-02-STZ nsd[1008]: 
can't bind udp socket 2804:XXXX:40:0:187:XXXX:159:11 at 53: Cannot assign 
requested address
2025-08-18T19:33:10.901166-03:00 DNS-AUTORITATIVO-02-STZ nsd[1008]: 
server initialization failed, nsd could not be started
2025-08-18T19:33:10.902333-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Main process exited, code=exited, status=1/FAILURE
2025-08-18T19:33:10.902418-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Failed with result 'exit-code'.
2025-08-18T19:33:10.902636-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
Failed to start nsd.service - Name Server Daemon.
2025-08-18T19:33:11.063181-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Scheduled restart job, restart counter is at 3.
2025-08-18T19:33:11.064997-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
Starting nsd.service - Name Server Daemon...
2025-08-18T19:33:11.132452-03:00 DNS-AUTORITATIVO-02-STZ nsd[1013]: nsd 
starting (NSD 4.12.0)
2025-08-18T19:33:11.132548-03:00 DNS-AUTORITATIVO-02-STZ nsd[1013]: 
can't bind udp socket 2804:XXXX:40:0:187:XXXX:159:11 at 53: Cannot assign 
requested address
2025-08-18T19:33:11.132582-03:00 DNS-AUTORITATIVO-02-STZ nsd[1013]: 
server initialization failed, nsd could not be started
2025-08-18T19:33:11.133930-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Main process exited, code=exited, status=1/FAILURE
2025-08-18T19:33:11.134018-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Failed with result 'exit-code'.
2025-08-18T19:33:11.134286-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
Failed to start nsd.service - Name Server Daemon.
2025-08-18T19:33:11.405316-03:00 DNS-AUTORITATIVO-02-STZ systemd[1]: 
nsd.service: Scheduled restart job, restart counter is at 4.



2025-08-21T16:46:50.802152-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
Starting unbound.service - Unbound DNS server...
2025-08-21T16:46:50.822538-03:00 DNS-RECURSIVO-02-STZ (unbound)[977]: 
unbound.service: Referenced but unset environment variable evaluates to 
an empty string: DAEMON_OPTS
2025-08-21T16:46:50.837820-03:00 DNS-RECURSIVO-02-STZ unbound[977]: Aug 
21 16:46:50 unbound[977:0] error: can't bind socket: Cannot assign 
requested address for 2804:XXXX:40:0:189:XXXX:159:83 port 53
2025-08-21T16:46:50.837885-03:00 DNS-RECURSIVO-02-STZ unbound[977]: Aug 
21 16:46:50 unbound[977:0] fatal error: could not open ports
2025-08-21T16:46:50.839261-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound.service: Main process exited, code=exited, status=1/FAILURE
2025-08-21T16:46:50.854375-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound.service: Failed with result 'exit-code'.
2025-08-21T16:46:50.854615-03:00 DNS-RECURSIVO-02-STZ systemd[1]: Failed 
to start unbound.service - Unbound DNS server.
2025-08-21T16:46:50.859030-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound-resolvconf.service - Unbound asyncronous resolvconf update 
helper was skipped because of an unmet condition check 
(ConditionFileIsExecutable=/sbin/resolvconf).
2025-08-21T16:46:50.963924-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound.service: Scheduled restart job, restart counter is at 1.
2025-08-21T16:46:50.966427-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
Starting unbound.service - Unbound DNS server...
2025-08-21T16:46:51.028833-03:00 DNS-RECURSIVO-02-STZ (unbound)[1008]: 
unbound.service: Referenced but unset environment variable evaluates to 
an empty string: DAEMON_OPTS
2025-08-21T16:46:51.034365-03:00 DNS-RECURSIVO-02-STZ unbound[1008]: Aug 
21 16:46:51 unbound[1008:0] error: can't bind socket: Cannot assign 
requested address for 2804:XXXX:40:0:189:XXXX:159:83 port 53
2025-08-21T16:46:51.034441-03:00 DNS-RECURSIVO-02-STZ unbound[1008]: Aug 
21 16:46:51 unbound[1008:0] fatal error: could not open ports
2025-08-21T16:46:51.035461-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound.service: Main process exited, code=exited, status=1/FAILURE
2025-08-21T16:46:51.050773-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound.service: Failed with result 'exit-code'.
2025-08-21T16:46:51.051016-03:00 DNS-RECURSIVO-02-STZ systemd[1]: Failed 
to start unbound.service - Unbound DNS server.
2025-08-21T16:46:51.052126-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound-resolvconf.service - Unbound asyncronous resolvconf update 
helper was skipped because of an unmet condition check 
(ConditionFileIsExecutable=/sbin/resolvconf).
2025-08-21T16:46:51.401249-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound.service: Scheduled restart job, restart counter is at 2.
2025-08-21T16:46:51.402439-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
Starting unbound.service - Unbound DNS server...
2025-08-21T16:46:51.453759-03:00 DNS-RECURSIVO-02-STZ (unbound)[1020]: 
unbound.service: Referenced but unset environment variable evaluates to 
an empty string: DAEMON_OPTS
2025-08-21T16:46:51.459656-03:00 DNS-RECURSIVO-02-STZ unbound[1020]: Aug 
21 16:46:51 unbound[1020:0] error: can't bind socket: Cannot assign 
requested address for 2804:XXXX:40:0:189:XXXX:159:83 port 53
2025-08-21T16:46:51.459742-03:00 DNS-RECURSIVO-02-STZ unbound[1020]: Aug 
21 16:46:51 unbound[1020:0] fatal error: could not open ports
2025-08-21T16:46:51.460793-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound.service: Main process exited, code=exited, status=1/FAILURE
2025-08-21T16:46:51.473953-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound.service: Failed with result 'exit-code'.
2025-08-21T16:46:51.474173-03:00 DNS-RECURSIVO-02-STZ systemd[1]: Failed 
to start unbound.service - Unbound DNS server.
2025-08-21T16:46:51.475419-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound-resolvconf.service - Unbound asyncronous resolvconf update 
helper was skipped because of an unmet condition check 
(ConditionFileIsExecutable=/sbin/resolvconf).
2025-08-21T16:46:51.824571-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound.service: Scheduled restart job, restart counter is at 3.
2025-08-21T16:46:51.825656-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
Starting unbound.service - Unbound DNS server...
2025-08-21T16:46:51.878177-03:00 DNS-RECURSIVO-02-STZ (unbound)[1031]: 
unbound.service: Referenced but unset environment variable evaluates to 
an empty string: DAEMON_OPTS
2025-08-21T16:46:52.109339-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
Started unbound.service - Unbound DNS server.
2025-08-21T16:46:52.109552-03:00 DNS-RECURSIVO-02-STZ systemd[1]: 
unbound-resolvconf.service - Unbound asyncronous resolvconf update 
helper was skipped because of an unmet condition check 
(ConditionFileIsExecutable=/sbin/resolvconf).
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