For security reasons, I don’t like that “Debian/Ubuntu” shows up on my sshd server string.
You can see the sshd server identification string by telnetting to port 22.
$ telnet ngmarley.com 22 Trying 106.187.97.211... Connected to ngmarley.com. Escape character is '^]'. SSH-2.0-OpenSSH_6.0p1 Debian-3ubuntu1 ^] telnet> quit Connection closed.
It’s very simple to just remove the “Debian…” part off the end.
Just edit /etc/ssh/sshd_config and append
DebianBanner no
to it.
Then re-start your sshd:
service ssh restart
… and now verify that it’s gone:
$ telnet ngmarley.com 22 Trying 106.187.97.211... Connected to ngmarley.com. Escape character is '^]'. SSH-2.0-OpenSSH_6.0p1 ^] telnet> quit Connection closed.