查看失败的ip，并将ip追加到黑名单，禁止ip访问Linux

#iplist=$(/bin/lastb |awk '{print $3}'|sort|uniq -c|awk '{if ($1>3) print $2}')
#查看失败的登录记录  登录次数大于1500次的ip  且不是192的内网ip
iplist=$(/bin/lastb |awk '{print $3}'|sort|uniq -c|awk '{if ($1>1500) print $2}' | grep -v "^192.")   
# 追加到黑名单并清空登录日志
for ip in ${iplist}
do
        echo ALL: ${ip} >> /etc/hosts.deny
        echo > /var/log/btmp
done