动态域名解析IP并修改防火墙规则

#!/bin/bash
while true
do
#刷新DNS
nscd -i hosts
OLD_IP=`iptables -L -n | grep :22 | awk  '{print $4}'| head -1`
NEW_IP=`ping www.baidu.com -c1 -n| grep from | awk '{ print $4 }'| awk -F":" '{print $1}'`
if [ $NEW_IP != $OLD_IP ]
then
sed -i  's/'$OLD_IP'/'$NEW_IP'/g' /etc/sysconfig/iptables
/etc/init.d/iptables restart
echo " `date +%Y-%m-%d\ %H:%M:%S` Ip  has changed, the new ip is  $NEW_IP"  >> /tmp/ip_change.log
fi
#每60秒判断一次
sleep 60
done