/etc/motd (Message of the Day)
/etc/ssh/sshd_config: Change the setting PrintLastLog to "no", this will disable the "Last login" message.
And then restart your sshd.
sudo /etc/init.d/ssh restart
Quelle: https://serverfault.com/questions/407033/how-can-i-edit-the-welcome-message-when-ssh-start