iptables命令执行正常，但机器重后就出现错误

movq

这是我的防火墙脚本，eth0:192.168.1.1接ADSL，eth1:192.168.0.1接交换机，想达到如下目的：1、内网机器共享ADSL上网。2、对外网只开放22和5430端口（用于被动式FTP）
请教各位：、1、此脚本是否合理，还有没有漏洞？
echo "Enable IP Forwarding..."
echo 1 >/proc/sys/net/ipv4/ip_forward
echo "Starting iptables rules..."
/sbin/modprobe iptable_filter
/sbin/modprobe ip_tables
/sbin/modprobe iptable_nat
/sbin/modprobe ip_nat_ftp
/sbin/modprobe ip_conntrack_ftp


iptables -F INPUT
iptables -F FORWARD
iptables -F OUTPUT
iptables -F POSTROUTING -t nat
iptables -F PREROUTING -t nat

iptables -P INPUT DROP
iptables -P FORWARD DROP
iptables -P OUTPUT ACCEPT

iptables -A INPUT -i lo -j ACCEPT
iptables -A INPUT -i eth1 -j ACCEPT
iptables -A INPUT -i ppp0 -m state --state ESTABLISHED,RELATED -j ACCEPT

iptables -A FORWARD -s 192.168.0.0/24 -j ACCEPT
iptables -A FORWARD -i ppp0 -m state --state ESTABLISHED,RELATED -j ACCEPT
iptables -t nat -A POSTROUTING -o ppp0 -s 192.168.0.0/24 -j MASQUERADE

2、此脚本粘贴到终端执行正常，上述目的都能达到，但是用iptables-save > iptables后，iptables文件如下：
Generated by iptables-save v1.2.7a on Sat Aug 20 19:43:30 2005
*nat
REROUTING ACCEPT [126:7701]
OSTROUTING ACCEPT [2:155]
:OUTPUT ACCEPT [2:155]
-A POSTROUTING -s 192.168.0.0/255.255.255.0 -o ppp0 -j MASQUERADE
COMMIT
# Completed on Sat Aug 20 19:43:30 2005
# Generated by iptables-save v1.2.7a on Sat Aug 20 19:43:30 2005
*filter
:INPUT DROP [347:20513]
:FORWARD DROP [0:0]
:OUTPUT ACCEPT [169:60408]
:RH-Lokkit-0-50-INPUT - [0:0]
-A INPUT -i lo -j ACCEPT
-A INPUT -i eth1 -j ACCEPT
-A INPUT -i ppp0 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A FORWARD -s 192.168.0.0/255.255.255.0 -j ACCEPT
-A FORWARD -i ppp0 -m state --state RELATED,ESTABLISHED -j ACCEPT
-A RH-Lokkit-0-50-INPUT -p tcp -m tcp --dport 5430 --tcp-flags SYN,RST,ACK SYN -j ACCEPT
-A RH-Lokkit-0-50-INPUT -p tcp -m tcp --dport 22 --tcp-flags SYN,RST,ACK SYN -j ACCEPT
-A RH-Lokkit-0-50-INPUT -i lo -j ACCEPT
-A RH-Lokkit-0-50-INPUT -p tcp -m tcp --dport 0:1023 --tcp-flags SYN,RST,ACK SYN -j REJECT --reject-with icmp-port-unreachable
-A RH-Lokkit-0-50-INPUT -p tcp -m tcp --dport 2049 --tcp-flags SYN,RST,ACK SYN -j REJECT --reject-with icmp-port-unreachable
-A RH-Lokkit-0-50-INPUT -p udp -m udp --dport 0:1023 -j REJECT --reject-with icmp-port-unreachable
-A RH-Lokkit-0-50-INPUT -p udp -m udp --dport 2049 -j REJECT --reject-with icmp-port-unreachable
-A RH-Lokkit-0-50-INPUT -p tcp -m tcp --dport 6000:6009 --tcp-flags SYN,RST,ACK SYN -j REJECT --reject-with icmp-port-unreachable
-A RH-Lokkit-0-50-INPUT -p tcp -m tcp --dport 7100 --tcp-flags SYN,RST,ACK SYN -j REJECT --reject-with icmp-port-unreachable
COMMIT
# Completed on Sat Aug 20 19:43:30 2005

重启机器后，内网机器就无法上网了，必须重新手动执行脚本命令才行，这是何原因？