SSH banner not showing

Question

I have a fresh installation of OpenSSH. In the /etc/ssh/sshd_config I have the following entry: Banner /etc/issue.net I have restarted the SSH deamon using: sudo /etc/init.d/ssh restart. Now, whenever I try to run ssh user@localhost it works just fine, except it doesn't show the pre-login banner.

What can cause this problem?

Answer 1

Possibilities:

1. sshd is reading a different config file from the one you've edited
2. sshd is running in a chroot environment which doesn't include the file you specified
3. sshd didn't really restart, perhaps because you have systemd and the init script for ssh exits when it realises upstart isn't running (in this case, use systemctl restart ssh.service).
4. You're using ssh protocol 1 instead of 2.

Answer 2

I did not see mentioned here, but even if the banner is enabled in sshd_config and sshd is fully restarted, the user's own ~/.ssh/config can suppress the banner using: LogLevel QUIET As the op took the solution but noone mentioned this, I'd like to add that here for future searchers

Answer 3

Ubuntu 14.04 uses upstart, and /etc/init.d/ssh restart doesn't restart sshd if upstart is running, so sshd isn't recognizing your changes to /etc/ssh/sshd_config. Instead, run this:

# restart ssh

You can verify that sshd was restarted by running

# ps -f -p $(pgrep sshd)

or

# ps -f -p $(status ssh | awk '{ print $NF }')

and checking that the start time (STIME) is more recent than the time you ran the command to restart it.