I first noticed that I could not ssh to my host, was getting connection refused error. Then I tried to connect over IPv6 address and it worked. I checked with `ss -tlnp | grep 22` and found out that sshd was only listening on [::]:22. Then I tried almost everything to bind it to 0.0.0.0 without any luck. Even when I only specified 0.0.0.0 as bind interface, it was still binding to [::] instead.
I also noticed that my manually compiled sslh behaved the same way. Last time it was compiled on Ubuntu 22.04, so I decided to rebuild it on 24.04 and it started to work properly. I believe, there was some change in libc which either requires all network related software recompiled from source. Because like I said, almost every network related software behaves the same. While net.ipv6.bindv6only=0 is the default, it doesn't explain why net.ipv6.bindv6only=1 works incorrectly. It is not supposed to replace 0.0.0.0 with [::], it is supposed to stop applications to bind to IPv4 interfaces when they are configured to bind to [::] only explicitly. Also, it doesn't explain why recompiling applications from source fixes the issue. -- 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
