1) By default sshd server turns off this feature.
2) Login as the root user; create your login banner file:
# vi /etc/ssh/sshd-banner
Append text:
Welcome to nixCraft Remote Login!
3) Open sshd configuration file /etc/sshd/sshd_config using a text editor:
# vi /etc/sshd/sshd_config
4) Add/edit the following line:
Banner /etc/ssh/sshd-banner
5) Save file and restart the sshd server:
systemctl restart sshd
原文:
https://www.cyberciti.biz/tips/change-openssh-sshd-server-login-banner.html