Comment 2 for bug 1687482

I'm running xenial. After I saw your comment I tried it on zesty and have yet to run into this bug on zesty. I haven't tried in the same environment yet though, I can try that later this week as well as get an apport-collect done.

As you can see below, the last login reports an ipv6 address. I verified it is using ipv6 using iftop as well. I also tried your trivial case and the same thing happened.

We are running freeipa, I don't know if that would have an effect or not.

If it's fixed in zesty, is there any way to get the same fix into xenial?

bryceml@ratpoison:~$ ssh -4 sake
Welcome to Ubuntu 16.04.2 LTS (GNU/Linux 4.4.0-75-generic x86_64)

 * Documentation: https://help.ubuntu.com
 * Management: https://landscape.canonical.com
 * Support: https://ubuntu.com/advantage

0 packages can be updated.
0 updates are security updates.

Last login: Tue May 2 08:50:11 2017 from 2620:10f:3007:a068:1a66:daff:fe1f:a85
bryceml@sake:~$ logout
Connection to sake closed.
bryceml@ratpoison:~$ ssh -4 sake
Welcome to Ubuntu 16.04.2 LTS (GNU/Linux 4.4.0-75-generic x86_64)

 * Documentation: https://help.ubuntu.com
 * Management: https://landscape.canonical.com
 * Support: https://ubuntu.com/advantage

0 packages can be updated.
0 updates are security updates.

Last login: Tue May 2 08:50:27 2017 from 2620:10f:3007:a068:1a66:daff:fe1f:a85
bryceml@sake:~$ host sake
sake.cs.byu.edu has address 192.168.168.107
sake.cs.byu.edu has IPv6 address 2620:10f:3007:a068:1a66:daff:fe1f:d96f
bryceml@sake:~$

bryceml@ratpoison:~$ ssh -4 ip6-localhost
The authenticity of host 'ip6-localhost (<no hostip for proxy command>)' can't be established.
ECDSA key fingerprint is SHA256:nhU3sXqrZoF3zNUxlWAfuLebsMSFhRuycFFWHlL2RRY.
Are you sure you want to continue connecting (yes/no)? yes
Warning: Permanently added 'ip6-localhost' (ECDSA) to the list of known hosts.
Welcome to Ubuntu 16.04.2 LTS (GNU/Linux 4.4.0-75-generic x86_64)

 * Documentation: https://help.ubuntu.com
 * Management: https://landscape.canonical.com
 * Support: https://ubuntu.com/advantage

0 packages can be updated.
0 updates are security updates.

Last login: Tue May 2 08:43:46 2017 from 2620:10f:3007:a080:1a66:daff:fe1f:1057
bryceml@ratpoison:~$ logout
Connection to ip6-localhost closed.
bryceml@ratpoison:~$ ssh -4 ip6-localhost
Welcome to Ubuntu 16.04.2 LTS (GNU/Linux 4.4.0-75-generic x86_64)

 * Documentation: https://help.ubuntu.com
 * Management: https://landscape.canonical.com
 * Support: https://ubuntu.com/advantage

0 packages can be updated.
0 updates are security updates.

Last login: Tue May 2 08:57:16 2017 from ::1
bryceml@ratpoison:~$