怎样用iptable做NAT+FTP?

linker_yxj

用小区宽带,通过ppp0上网,用iptables做NAT,用VSFTP做FTP服务器,该怎样写iptables脚本.
我的这断脚本只能实现NAT,不能FTP(VSFTP已配好),
#!/bin/sh
modprobe ip_nat_ftp
modprobe ip_conntrack_ftp
echo 1 > /proc/sys/net/ipv4/ip_forward

iptables -F -t filter
iptables -X -t filter
iptables -Z -t filter
iptables -F -t nat
iptables -X -t nat
iptables -Z -t nat

iptables -P INPUT DROP
iptables -P OUTPUT ACCEPT
iptables -P FORWARD DROP
iptables -t nat -P PREROUTING ACCEPT
iptables -t nat -P POSTROUTING ACCEPT
iptables -t nat -P OUTPUT ACCEPT

iptables -A FORWARD ! -i ppp0 -m state --state NEW -j ACCEPT
iptables -A FORWARD -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -A INPUT ! -i ppp0 -m state --state NEW -j ACCEPT
iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -t nat -A POSTROUTING -o ppp0 -j MASQUERADE

大熊宝宝

iptables -A INPUT --dport 21 -j ACCEPT