A few days ago I tried to remove system banner that new Ubuntu is displaying on login. System banner looks something like this:
Linux linux-monitor 2.6.35-22-server #33-Ubuntu SMP Sun Sep 19 20:48:58 UTC 2010 x86_64 GNU/Linux
Welcome to the Ubuntu Server!
No mather what I tried, motd was always updated. First I tried simple echo -n > /etc/motd and nothing happened. When I tried to login again, banner was still there. Then I tried this: echo -n > /etc/motd.tail and still, banner was there. I remembered that ssh can display motd too. So I edited my /etc/ssh/sshd_config and set PrintMotd to no. Still nothing. Something always updated motd file. So I googled around a little. Motd is controlled by pam_motd module. We can disable system banner by comment out the lines that contain pam_motd. We can find pam_motd in files /etc/pam.d/login and /etc/pam.d/sshd. Now, if you try to login again, system banner shouldn’t be shown.