how to set up SSH on Ubuntu server

The narrator opens the SSH configuration file to modify default behaviors. you can use this command as well

 nano/etc/ssh/sshd/config

For improved security, the default port 22 is changed to 9995. This helps protect the server from automated bots that typically target port 22.
The setting PermitRootLogin is changed to “no”. This prevents users from logging in directly as the “root” user, requiring them to log in as a standard user first and then switch to root if necessary.
There is a brief mention of disabling password authentication entirely in favor of private/public keys for maximum security, though this is treated as an advanced step.

After saving the configuration file, the SSH service must be restarted for the changes to take effect.
The connection must now use the new port (9995).
Direct login as root is successfully denied, confirming the new security rules are active.