Is sshd not accessible at all over ipv4? How did you notice that sshd was not listening on ipv4?
In the default case, we should end up with ssh.socket listening on [::]:22, but with IPV6_V6ONLY=0 so that sshd is still accessible over ipv4. > Setting net.ipv6.bindv6only=0 also helps, but that's not a solution. I think this is the default on Ubuntu, no? If your system does have net.ipv6.bindv6only=1, and you don't want to change it, a workaround for now should be to do: $ mkdir -p /etc/systemd/systemd/ssh.socket.d/ $ cat > /etc/systemd/system/ssh.socket.d/bindipv6only-both.conf << EOF [Socket] BindIPv6Only=both EOF which has the effect of setting IPV6_V6ONLY to 0 for this particular socket. We should probably fix sshd-socket-generator to automatically do this in certain cases. ** Changed in: openssh (Ubuntu) Importance: Undecided => Medium ** Changed in: openssh (Ubuntu) Status: New => Incomplete ** Changed in: openssh (Ubuntu) Status: Incomplete => Confirmed ** Tags added: rls-nn-incoming -- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to openssh in Ubuntu. https://bugs.launchpad.net/bugs/2080216 Title: sshd cannot bind to IPv4 interfaces Status in openssh package in Ubuntu: Confirmed Bug description: After upgrading from 22.04 to 24.04 I noticed that my sshd only listening on IPv6 interface (::), while previously it was listening both IPv4 (0.0.0.0) and IPv6 (::). I tried to explicitly specify ListenAddress 0.0.0.0 (assuming it would bind to IPv4 only) but after restart sshd was still listening on IPv6 only. This problem affects other packages as well, for example, openvpn. Rebuilding applications from sources seems to fix the issue. Setting net.ipv6.bindv6only=0 also helps, but that's not a solution. ProblemType: Bug DistroRelease: Ubuntu 24.04 Package: openssh-server 1:9.6p1-3ubuntu13.5 ProcVersionSignature: Ubuntu 6.8.0-41.41-generic 6.8.12 Uname: Linux 6.8.0-41-generic x86_64 ApportVersion: 2.28.1-0ubuntu3.1 Architecture: amd64 CasperMD5CheckResult: unknown Date: Tue Sep 10 16:45:54 2024 ProcEnviron: LANG=C.UTF-8 PATH=(custom, no user) SHELL=/bin/bash TERM=screen.xterm-256color SourcePackage: openssh UpgradeStatus: Upgraded to noble on 2024-09-10 (0 days ago) To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/2080216/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp