debcrafters-packages team mailing list archive

[Nick Rosbrook <2122601@xxxxxxxxxxxxxxxxxx>]

Sorry, I was trying to offer the most direct solution, but here is more
detail.

First - unless you have a configuration for the socket that is more
complicated than what can be achieved with the Port, ListenAddress, and
AddressFamily options in sshd_config[1], then I strongly recommend using
e.g. /etc/ssh/sshd_config.d/custom.conf for your port configuration
instead of using ssh.socket overrides.

Second - if you want your /etc/system/systemd/ssh.socket.d/override.conf
to work, you need to specify the address family explicitly, *or*
override the value of BindIPv6Only=ipv6-only [2], too. For a more
detailed explanation, please see bug 2118912 [3].

In other words, because your override is:

# /etc/systemd/system/ssh.socket.d/override.conf
[Socket]
ListenStream=
ListenStream=22

rather than:

# /etc/systemd/system/ssh.socket.d/override.conf
[Socket]
ListenStream=
ListenStream=0.0.0.0:22
ListenStream=[::]:22

or:

# /etc/systemd/system/ssh.socket.d/override.conf
[Socket]
ListenStream=
ListenStream=22
BindIPv6Only=both

you are actually overriding the default ssh.socket unit in a way that
says "only listen on port 22 via IPv6, not IPv4".

Hence, I hope it is clear why I recommend simply using
/etc/ssh/sshd_config.d/custom.conf.

[1] https://manpages.ubuntu.com/manpages/noble/en/man5/sshd_config.5.html
[2] https://www.freedesktop.org/software/systemd/man/latest/systemd.socket.html#BindIPv6Only=
[3] https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/2118912

-- 
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https://bugs.launchpad.net/bugs/2122601

Title:
  ssh access on port 22 inhibited

Status in openssh package in Ubuntu:
  Incomplete

Bug description:
  Ubuntu 24.04.3 LTS

  ssh:
    Installed: (none)
    Candidate: 1:9.6p1-3ubuntu13.13
    Version table:
       1:9.6p1-3ubuntu13.13 500
          500 http://de.archive.ubuntu.com/ubuntu noble-updates/main amd64 Packages
       1:9.6p1-3ubuntu13.11 500
          500 http://security.ubuntu.com/ubuntu noble-security/main amd64 Packages
       1:9.6p1-3ubuntu13 500
          500 http://de.archive.ubuntu.com/ubuntu noble/main amd64 Packages

  
  I had changed the ssh port thru /etc/systemd/system/ssh.socket.d/override.conf:

  [Socket]
  ListenStream =
  ListenStream = 24427

  The team requested to have that returned to the default port 22. So I
  changed the file to

  [Socket]
  ListenStream =
  ListenStream = 22

  With a recent update I could no longer ssh into the machine. Two solutions:
  1. Use sshd instead of ssh.socket
  2. Remove or rename the above control file so that it is not read.

  I.e. having port 22 defined in the controlfile breaks access.
  Annoying. A fix will be highly appreciated.

  Others ran into the same issue:
  https://blog.dummzeuch.de/2025/09/09/troubleshooting-a-ssh-socket-
  problem/

  ProblemType: Bug
  DistroRelease: Ubuntu 24.04
  Package: ubuntu-release-upgrader-core 1:24.04.27
  ProcVersionSignature: Ubuntu 6.8.0-79.79-generic 6.8.12
  Uname: Linux 6.8.0-79-generic x86_64
  ApportVersion: 2.28.1-0ubuntu3.8
  Architecture: amd64
  CasperMD5CheckResult: pass
  CrashDB: ubuntu
  CrashReports: 600:0:0:277414:2025-09-03 13:34:44.691428521 +0000:2025-09-03 13:34:44.676428638 +0000:/var/crash/qant-native-computing-toolkit.0.crash
  Date: Thu Sep 11 14:25:32 2025
  InstallationDate: Installed on 2025-04-17 (147 days ago)
  InstallationMedia: Ubuntu-Server 24.04.2 LTS "Noble Numbat" - Release amd64 (20250216.2)
  PackageArchitecture: all
  ProcEnviron:
   LANG=en_US.UTF-8
   PATH=(custom, no user)
   SHELL=/bin/bash
   TERM=linux
  SourcePackage: ubuntu-release-upgrader
  Symptom: release-upgrade
  UpgradeStatus: No upgrade log present (probably fresh install)

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