redhat9+adsl透明代理上网iptables问题（附firewall代码）？

太阳风

实现redhat9+adsl+squid+iptables透明代理上网：在firewall中只添加以下代码：
/sbin/iptables -F -t nat
iptables -t nat -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128
#将eth1的所有针对80端口的访问重定向到3128端口。
iptables -t nat -A POSTROUTING -s 192.168.1.0/24 -o ppp0 -j MASQUERADE
代理上网正常。现在希望用iptables进行控制。参照网上许多代码。如下：
#!/bin/sh

touch /var/lock/subsys/local

# Enabling IP Forwarding......"
echo "Enabling IP Forwarding........"
echo 1 > /proc/sys/net/ipv4/ip_forward

# Enabling iptables rules
# Internet Configuration.
EXT_IF="ppp0"
INT_IF="eth1"
LAN_IP_RANGE="192.168.0.0/24"
TRUSTED_TCP_PORT="22 25 53 80 110 143 443 3128 6000 6001 6002 7100"

# 加载模块
echo "modprobe modules"
modprobe ip_tables
modprobe ip_nat_ftp
modprobe ip_conntrack
modprobe ip_conntrack_ftp

# iptables规则初始化
echo "Enabling iptables rules"

iptables -F -t nat

iptables -P FORWARD DROP

# 打开信任端口
echo "Open trusted ports....."
iptables -N services
for PORT in $TRUSTED_TCP_PORT; do
iptables -A services -i $EXT_IF -p tcp --dport $PORT -j ACCEPT
done

iptables -t nat -A PREROUTING -i eth1 -p tcp -m tcp --dport 80 -j REDIRECT --to-ports 3128

iptables -t nat -A POSTROUTING -s 192.168.0.0/24 -o ppp0 -j MASQUERADE

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

iptables -A FORWARD -f -m limit --limit 100/s --limit-burst 100 -j ACCEPT
iptables -A FORWARD -p icmp -m limit --limit 1/s --limit-burst 10 -j ACCEPT

# 允许udp访问
iptables -A FORWARD -p udp -d $LAN_IP_RANGE -i $EXT_IF -j ACCEPT

# Open SSH
echo "Open SSH....."
iptables -A OUTPUT -o $EXT_IF -p tcp --sport 1024:65535 -d any/0 --dport 22 -j ACCEPT
iptables -A INPUT -i $EXT_IF -p tcp ! --syn -s any/0 --sport 22 --dport 1024:65535 -j ACCEPT

## iptables END

echo "Enabling Squid"
/usr/local/squid/sbin/squid

echo "Enabling ADSL"
adsl-start
配置后发现udp访问正常。ping正常。但是无法打开网页！而且无法用startx启动xwindow。请问如何解决？