Ubuntu
openssh package

  1. Bug #1254085
  2. Comment #37

Comment 37 for bug 1254085

Revision history for this message
fhsm (fhsm) wrote :

I'm running into hung ssh connection and it is crazy making because I'm getting inconsistent behavior across 16.10 boxes.

I've got two newly installed 16.10 boxes ($ ssh -V: OpenSSH_7.3p1 Ubuntu-1, OpenSSL 1.0.2g 1 Mar 2016). I'll call them Box1 and Box2. They are in in adjacent ports on switch that has not had any changes in years and on which all other systems are functioning.

I've got four clients: one OS X 10.9 (OpenSSH_6.2p1,OSSLShim 0.9.8r 8 Dec 2011), OS X 10.11 (OpenSSH_6.9p1, LibreSSL 2.1.8), Box1, and Box2.

I can connect to Box1 from the other three clients without any problem. Works as expected.

I can ONLY connect to Box2 from OS X 10.9 and itself (i.e. ssh me@localhost). I cannot get to it from Box1, I cannot get to it from OS X 10.11. I have swapped the two OS X boxes around on the network and also the two 16.10 boxes such that I'm confident that the ability to connect is a function of the client-server combination not the network link between them. ssh -vvv into Box2 from all of the failing clients hangs as above, expecting SSH2_MSG_KEX_ECDH_REPLY.

This behavior / bug is so perplexing I'm unsure of it's relevance. I see two factors of interest:
 - Two ubuntu 16.10 sshds are behaving differently despite stock config across the two;
 - The ubuntu 16.10 is unable to connect to an sshd that one of two OS X ssh clients is able to connect two.

Since the two just got installed they haven't had much time to diverge. The only differences between box1 and box2 are: (1) box2 is a few updates behind and (2) although both have LXD installed only box2 has had a container launched on it. Unfortunately prior to racking only the 10.9 system had ssh-ed into these boxes.

I'm going to sit on this for now in case someone interesting in trying to get the Ubuntu ssh client to function - or - someone curious about the divergent behavior of the Ubuntu sshd can give guidance on how to turn this from a odd +1 report into something more useful. If not I'll do a little more troubleshooting (install the pending updates [initramfs-tools initramfs-tools-bin initramfs-tools-core isc-dhcp-client isc-dhcp-common libglib2.0-0 libglib2.0-data liblxc1 lxc-common], purge LXD) to see if I stumble onto something useful and failing that nuke and pave.