Login to our server as root, if you don’t have root access, you can’t use this tutorial.
Then type in the following: pico /etc/motd (or nano /etc/motd)
Now type in the security login message you wish all users to see once they login to your server through SSH. Try something like this as a start:
This computer system is for authorized users only. All activity is logged and regularly checked by systems personal. Individuals using this system without authority or in excess of their authority are subject to having all their services revoked. Any illegal services run by user or attempts to take down this server or its services will be reported to local law enforcement, and said user will be punished to the full extent of the law. Anyone using this system consents to these terms.