IPtable Forward Port

This is sample rule to forward rdp to host.  LinixGateway-->>Windows Server2003

#echo 1 > /proc/sys/net/ipv4/ip_forward

Forward rule Listen port 3000 forward to 3389 

#/sbin/iptables -A FORWARD -i eth0 -o eth1 -p tcp --dport 3000 -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT
#/sbin/iptables -A PREROUTING -t nat -p tcp -i eth0 --dport 3000 -j DNAT --to-destination 172.31.255.2:3389

WWW Fileshare

#/sbin/iptables -A FORWARD -i eth0 -o eth1 -p tcp --dport 8000 -m state --state NEW,ESTABLISHED,RELATED -j ACCEPT
#/sbin/iptables -A PREROUTING -t nat -p tcp -i eth0 --dport 8000 -j DNAT --to-destination 172.31.255.2:8000

#/sbin/iptables -t nat -A POSTROUTING -o eth0 -j MASQUERADE

Another Port Forward

/sbin/iptables -t filter -A FORWARD   -p tcp -m tcp --syn  --sport 1024:65535  --dport 3389:3390   -m state --state NEW -j NEWACCEPT
/sbin/iptables -t filter -A OUTPUT  -p tcp -m tcp --syn  --sport 1024:65535  --dport 3389:3390  -m state --state NEW -j NEWACCEPT
/sbin/iptables -t filter -A INPUT  -p tcp -m tcp --syn  --sport 1024:65535  --dport 3389:3390   -m state --state NEW -j NEWACCEPT
/sbin/iptables -t nat -A PREROUTING -i ppp0 -p tcp -m tcp --syn -s 0.0.0.0/0.0.0.0 --sport 1024:65535 -d 202.176.89.172/255.255.255.255 --dport 3389:3390   -m state --state NEW -j DNAT --to-destination 192.168.4.126 
/sbin/iptables -t filter -A FORWARD -i ppp0 -o eth1 -p tcp -m tcp --syn -s 0.0.0.0/0.0.0.0 --sport 1024:65535 -d 192.168.4.126/255.255.255.255 --dport 3389:3390   -m state --state NEW -j NEWACCEPT