HI I ALWAYS FORGOT THE CONFIGURATION AND ALWAYS NEED TO CONVERT WITH IPTABLES THE GUIDE IN RATHENA.
IN THIS REGARDS I JUST WANNA SHARE SO WHEN I GOOGLE IT I WILL NOT FORGET ABOUT IT.
sysctl net.ipv4.ip_forward=1
iptables -t nat -A POSTROUTING -j MASQUERADE
iptables -t nat -A PREROUTING -p tcp --dport 6121 -j DNAT --to-destination XXX.XXX.XXX.XXX:6121
iptables -t nat -A PREROUTING -p tcp --dport 5121 -j DNAT --to-destination XXX.XXX.XXX.XXX:5121
iptables -t nat -A PREROUTING -p tcp --dport 6900 -j DNAT --to-destination XXX.XXX.XXX.XXX:6900
iptables-save > /etc/iptables_rules
iptables-save > /etc/iptables_rules
iptables -A INPUT -p tcp --dport 6900 -m state --state NEW -j ACCEPT
iptables -A INPUT -p tcp --dport 6121 -m state --state NEW -j ACCEPT
iptables -A INPUT -p tcp --dport 5121 -m state --state NEW -j ACCEPT
iptables -A INPUT -p udp --dport 6900 -m state --state NEW -j ACCEPT
iptables -A INPUT -p udp --dport 6121 -m state --state NEW -j ACCEPT
iptables -A INPUT -p udp --dport 5121 -m state --state NEW -j ACCEPT