|  | 
 
| 这份脚本是先前的!我执行这份后我的内网可以上网了,相应的samba,dns,http,dns,vpn,dhcp,qmail服务也正常!但我发现安全系数不高,所以就写了第二份脚本!大家先看我的第一分脚本: 说明:eth1是内网!eth0是外网也就是ppp0
 echo '1'>/proc/sys/net/ipv4/ip_forward
 iptables -F
 iptables -P INPUT DROP
 iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
 iptables -A INPUT -i eth1 -p tcp -m multiport --dports 443,139,80,21,53,110,25 -j ACCEPT
 iptables -A INPUT -i eth1 -p udp -m multiport --dports 138,137,67,53 -j ACCEPT
 iptables -A INPUT -p tcp --dport 1723 -j ACCEPT
 iptables -A INPUT -p gre -j ACCEPT
 iptables -A INPUT -i ppp0 -p tcp -m multiport --dports 110,80,25 -j ACCEPT
 iptables -t nat -A POSTROUTING -o ppp0 -s 192.168.0.0/24 -j MASQUERADE
 iptables -A INPUT -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level INFO --log-prefix "IPT INPUT packet died: "
 iptables -A FORWARD -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level DEBUG --log-prefix "IPT FORWARD packet died: "
 iptables -A OUTPUT -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level DEBUG --log-prefix "IPT OUTPUT packet died: "
 
 接着看我的第二份脚本:我执行这分脚本后内网就不能上网了!我看了很多次脚本内容,没找到要怎么做,麻烦大家帮忙
 iptables -N bad_tcp_packets
 iptables -N allowed
 iptables -N icmp_packets
 iptables -P INPUT ACCEPT
 iptables -P FORWARD ACCEPT
 iptables -P OUTPUT ACCEPT
 iptables -t nat -P PREROUTING ACCEPT
 iptables -t nat -P POSTROUTING ACCEPT
 iptables -t nat -P OUTPUT ACCEPT
 iptables -t mangle -P PREROUTING ACCEPT
 iptables -t mangle -P OUTPUT ACCEPT
 iptables -F
 iptables -t nat -F
 iptables -t mangle -F
 iptables -X
 iptables -t nat -X
 iptables -t mangle -X
 iptables -P INPUT DROP
 iptables -P OUTPUT DROP
 iptables -P FORWARD DROP
 iptables -A bad_tcp_packets -p tcp ! --syn -m state --state NEW -j LOG --log-level INFO --log-prefix "New not syn:"
 iptables -A bad_tcp_packets -p TCP ! --syn -m state --state NEW -j DROP
 iptables -A allowed -p TCP --syn -j ACCEPT
 iptables -A allowed -p TCP -m state --state ESTABLISHED,RELATED -j ACCEPT
 iptables -A allowed -p TCP -j DROP
 iptables -A INPUT -p tcp -j bad_tcp_packets
 iptables -A INPUT -m state --state ESTABLISHED,RELATED -j ACCEPT
 iptables -A INPUT -i eth1 -p tcp -m multiport --dports 443,139,80,21,53,110,25 -j ACCEPT
 iptables -A INPUT -i eth1 -p udp -m multiport --dports 138,137,67,53 -j ACCEPT
 iptables -A INPUT -p tcp --dport 1723 -j ACCEPT
 iptables -A INPUT -p gre -j ACCEPT
 iptables -A INPUT -i ppp0 -p tcp -m multiport --dports 110,80,25 -j ACCEPT
 iptables -A INPUT -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level INFO --log-prefix "IPT INPUT packet died: "
 iptables -t nat -A POSTROUTING -o ppp0 -s 192.168.0.0/24 -j MASQUERADE
 iptables -A FORWARD -p TCP -j bad_tcp_packets
 iptables -A FORWARD -s 192.168.0.0/24 -p tcp --dport 80 -j ACCEPT
 iptables -A FORWARD -s 192.168.0.0/24 -p tcp --dport 25 -j ACCEPT
 iptables -A FORWARD -s 192.168.0.0/24 -p tcp --dport 110 -j ACCEPT
 iptables -A FORWARD -s 192.168.0.0/24 -p tcp --dport 21 -j ACCEPT
 iptables -A FORWARD -s 192.168.0.0/24 -p tcp --dport 53 -j ACCEPT
 iptables -A FORWARD -s 192.168.0.0/24 -p udp --dport 53 -j ACCEPT
 iptables -A FORWARD -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level DEBUG --log-prefix "IPT FORWARD packet died: "
 iptables -A OUTPUT -p ALL -s 127.0.0.1 -j ACCEPT
 iptables -A OUTPUT -p ALL -s 192.168.0.0/24 -j ACCEPT
 iptables -A OUTPUT -o ppp0 -j ACCEPT
 iptables -A OUTPUT -m limit --limit 3/minute --limit-burst 3 -j LOG --log-level DEBUG --log-prefix "IPT OUTPUT packet died:
 | 
 |