Prerequisites: 1. open external firewall (cisco, linksys,…) ports 20, 21, 990 and port range 49500:50000 to the local FTP server 192.168.xx.yy * port range ports can be random ports higher than 49151 and lower than 65535 2. open firewall for port 20,21,990  and port range 49500:50000 on ftp server # vim /etc/sysconfig/iptables -A RH-Firewall-1-INPUT -p…