Yes, I can understand the frustration here. The sshd socket activation feature in Ubuntu has evolved since it was first introduced in 22.10, and is finally settling now. However, I think this patch was still important to make so that we could fix bug 2080216, and to align the systemd unit defaults with the non-socket activated defaults in sshd.
I think a large part of the misunderstanding here is around systemd socket's ListenStream= option itself. Setting e.g. ListenStream=1234 has *always* meant "listen on port 1234 on ipv6", and "depending on the value of BindIPv6Only= this might result in the service being available via both IPv6 and IPv4 (default) or just via IPv6." [1] Hence, while adding custom overrides in /etc/systemd/systemd/ssh.socket.d/ etc. has always been supported, it is an advanced use case, and should be done with care. Most users should use the ListenAddress, Port, and AddressFamily options in /etc/ssh/sshd_config.d/ directly. In other words, if one wanted to add an override and ensure that sshd is listening on port 1234 on ipv4, it's more accurate to use ListenStream=0.0.0.0:1234 (or ListenStream=[::]:1234 for ipv6), not ListenStream=1234. Again, I understand the frustration, but I hope the information above provides helpful detail and context around the issue. [1] https://www.freedesktop.org/software/systemd/man/latest/systemd.socket.html#ListenStream= -- 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/2118912 Title: openssh-server unavailable after upgrade to 1:9.6p1-3ubuntu13.13 Status in openssh package in Ubuntu: Invalid Bug description: Ubuntu release: Ubuntu 24.04.2 LTS Package affected version: openssh-server:1:9.6p1-3ubuntu13.13 ------- After upgrading openssh-server:1:9.6p1-3ubuntu13.11 and openssh- server:1:9.6p1-3ubuntu13.12 to openssh-server:1:9.6p1-3ubuntu13.13 using unattended upgrades I found my Ubuntu 24 server unreachable via ssh. During intial setup I changed my ssh configuration adding TCP 1221 to its binding ports, to make that I followed these steps: cat << EOF > /etc/ssh/sshd_config.d/custom.conf Port 1221 Port 22 PermitRootLogin no PasswordAuthentication no EOF systemctl edit ssh.socket # adding these lines [Socket] ListenStream= ListenStream=22 ListenStream=1221 If I don't add any of those configuration changes to ssh.service and ssh.socket ssh is still available on standard tcp port 22 after upgrading to version 1:9.6p1-3ubuntu13.13. I I add those changes AFTER upgrading to version 1:9.6p1-3ubuntu13.13 the problem still occurr and ssh will become unavailable. Downgrade to previous version (1:9.6p1-3ubuntu13.11 or 1:9.6p1-3ubuntu13.12 fixes the problem without changing any of the previous customizations. Syntax to downgrade: sudo apt update; sudo apt install -y openssh-client=1:9.6p1-3ubuntu13.11 openssh-server=1:9.6p1-3ubuntu13.11 openssh-sftp-server=1:9.6p1-3ubuntu13.11 Steps to reproduce the problem on a new Ubuntu instance (tested both on AWS EC2 and GCP instances): 1. create a new instance based on Ubuntu 24LTS AMI 2. add TCP port 1221 (or any port you want) to ssh binding cat << EOF > /etc/ssh/sshd_config.d/custom.conf Port 1221 Port 22 PermitRootLogin no PasswordAuthentication no EOF systemctl edit ssh.socket # add these lines [Socket] ListenStream= ListenStream=22 ListenStream=1221 systemctl restart ssh.service ssh.socket 3. check ssh is available on TCP 22 and TCP 1221 (check firewall or security group) 4. upgrade system packages (make sure to upgrade openssh-server to version 1:9.6p1-3ubuntu13.13 sudo apt update ; sudo apt upgrade -y 5. sudo shutdown -r now 6. ssh unavailable after reboot but ssh.service and ssh.socket do not show any error or problem whatsoever. Thanks Tas To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/2118912/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : [email protected] Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
