防火墙范例

#!/bin/bash
# This program is for iptables' rules
# VBird 2003/05/02
#
# 0. PATH and modules
  PATH=/sbin:/bin:/usr/sbin:/usr/bin
  export PATH
  modprobe ip_tables
  modprobe iptable_nat
  modprobe ip_nat_ftp
  modprobe ip_nat_irc
  modprobe ip_conntrack
  modprobe ip_conntrack_ftp
  modprobe ip_conntrack_irc
#
# 1. clear the rules and make the policys
  iptables -F
  iptables -X
  iptables -Z
  iptables -F -t nat
  iptables -X -t nat
  iptables -Z -t nat
  iptables -P INPUT   DROP
  iptables -P OUTPUT  ACCEPT
  iptables -P FORWARD ACCEPT
  iptables -t nat -P PREROUTING  ACCEPT
  iptables -t nat -P POSTROUTING ACCEPT
  iptables -t nat -P OUTPUT      ACCEPT

#
# 2. NAT services
  echo "1" > /proc/sys/net/ipv4/ip_forward
  iptables -t nat -A POSTROUTING -s 192.168.10.0/24 -o eth1 -j MASQUERADE
#
# 3. Trust network and conditions
  iptables -A INPUT -m state --state ESTABLISHED,RELATED  -j ACCEPT 
  iptables -A INPUT -i lo -j ACCEPT
  iptables -A INPUT -m mac --mac-source XX:YY:ZZ:WW:QQ:PP -j ACCEPT 
# 上面这一行就是网络卡的卡号啦！

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