VOS3000 IPtables for port changing :
Use below rule to change your vos3000 client to access server on different port as 7899 or change as per your requirement
iptables -A PREROUTING -t nat -p tcp -m tcp –dport 1202 -j DNAT –to-destination :3720
iptables -A PREROUTING -t nat -p tcp -m tcp –dport 7899 -j DNAT –to-destination :1202
iptables -A PREROUTING -t nat -p tcp -m tcp –dport 1202 -j DNAT –to-destination :3720
iptables -A PREROUTING -t nat -p tcp -m tcp –dport 7899 -j DNAT –to-destination :1202
iptables -A PREROUTING -t nat -p tcp -m tcp –dport 3306 -j DROP
iptables -A PREROUTING -t nat -p tcp -m tcp –dport 2501 -j DROP
iptables -A PREROUTING -t nat -p tcp -m tcp –dport 1202 -j DROP
iptables -A PREROUTING -t nat -p tcp -m tcp –dport 1205 -j DROP
iptables -A PREROUTING -t nat -p tcp -m tcp –dport 143 -j DROP
iptables -A POSTROUTING -t nat -p tcp -m tcp –dport 7899 -j MASQUERADE
iptables -A POSTROUTING -t nat -p tcp -m tcp –dport 7899 -j MASQUERADE
Download IPtables list and modify as per your requirement
Download iptables
Edit and upload iptables.txt on your server and apply the iptables rule
#iptables-restore < /your upload path/iptables.txt