Step 1 : Log into N99panel. From under N99panel dashboard, click 'List Users'

Step 2 : In the following screen, please click 'SFTP FIlter (IPv4 based)'

Step 3 : In the next screen, you can enter valid IPv4 IP addresses or a CIDR range, with each entry on a single line.

Upon clicking submit, the system will allow SFTP future access only from the IPs belonging to the entered IPs or CIDR ranges

Submitting the box with no entries, disables the SFTP IPv4 filtering