The easiest way I found to reproduce was to monkey patch the python paramiko library. I've attached a short script which can be used to test a host. It requires either python-paramiko or python3-paramiko to run.
** Attachment added: "test_bug_1863930.py" https://bugs.launchpad.net/ubuntu/bionic/+source/openssh/+bug/1863930/+attachment/5332797/+files/test_bug_1863930.py -- 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/1863930 Title: SSH 1.99 clients fail to connect to openssh-server 1:7.6p1-4ubuntu0.3 Status in openssh package in Ubuntu: Fix Released Status in openssh source package in Bionic: New Bug description: 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. To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/openssh/+bug/1863930/+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
