Public bug reported: SSHD closes the connection and logs the error message below when a client presents a protoversion of "1.99":
Protocol major versions differ for X.X.X.X port X: SSH-2.0-OpenSSH_7.6p1 Ubuntu-4ubuntu0.3 vs. SSH-1.99-XXX RFC 4253 only states that clients should treat a server's protoversion of "1.99" as equivalent to "2.0"; however, some backward-compatible clients send a protoversion of "1.99" and expect the server to treat it as "2.0". This regression was introduced in openssh-portable 7.6p1 from commit 97f4d3083; fixes were implemented in commits 9e9c4a7e5 and c9c1bba06. I've attached a patch with both of those fixes. ** Affects: openssh (Ubuntu) Importance: Undecided Status: New ** Patch added: "protocol_major_version_mismatch_regression.patch" https://bugs.launchpad.net/bugs/1863930/+attachment/5329542/+files/protocol_major_version_mismatch_regression.patch -- You received this bug notification because you are a member of Ubuntu Bugs, which is subscribed to Ubuntu. https://bugs.launchpad.net/bugs/1863930 Title: SSH 1.99 clients fail to connect to openssh-server 1:7.6p1-4ubuntu0.3 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/1863930/+subscriptions -- ubuntu-bugs mailing list ubuntu-bugs@lists.ubuntu.com https://lists.ubuntu.com/mailman/listinfo/ubuntu-bugs