Linux学习之查看远端的端口是否通畅

以80端口为例解答

法一：此法常被用来检测是个远端端口是否通畅

 [root@oldboy ~]# telnet baidu.com
 Trying 123.125.114.144...
 Connected to baidu.com (123.125.114.144). #==>出现Connected表示连通了，说明百度的80端口开放的
 Escape character is '^]'. #==>ctrl+]退出此地。
 ^]
 telnet> quit
 Connection closed.

如果写脚本通过telnet检查端口可以用下面的方法：

 [root@oldboy ~]# echo -e "\n"|telnet baidu.com |grep Connected
 Connection closed by foreign host.
 Connected to baidu.com (123.125.114.144).

法二：通过nmap来检查端口是否通畅

 [root@oldboy ~]# nmap etiantian.org -p
 Starting Nmap 4.11 ( http://www.insecure.org/nmap/ ) at 2012-07-22 17:22 PDT
 Interesting ports on 211.100.98.99:
 PORT   STATE SERVICE
 /tcp open  http
 Nmap finished:  IP address ( host up) scanned in 0.417 seconds

如果写脚本通过nmap检查端口可以用下面的方法：

   PORT_COUNT=`nmap $ip_add  -p $port|grep open|wc -l`
   [[ $PORT_COUNT -ge  ]] && echo "$ip_add $port is ok." || echo "$ip_add $port is unknown."

法三：通过nc命令检查

 [root@oldboy ~]# nc -w   211.100.98.99  && echo ok
 ok
 [root@oldboy ~]# nc -w   8.8.8.8  && echo ok ||echo no
 ok

如果写脚本通过nc检查端口并监控memcache服务可以用下面的方法：

 export oldboyTimestampMemcachedIp=$
 export oldboyTimestampMemcachedPort=$
 export oldboyTitle=NAGIOS
 export oldboyTimestampMD5=4ED06F8D41B9264OLD0BOY30BE5212BB7E34
 export wwwServerIp=$
 export wwwServerPort=$

 printf "delete $oldboyTimestampMD5\r\n" | nc $oldboyTimestampMemcachedIp $oldboyTimestampMemcachedPort >/dev/null >&
 sleep
 judge=($(printf "HEAD /oldboy/$oldboyTitle HTTP/1.1\r\nHost: $5\r\n\r\n" | nc $wwwServerIp $wwwServerPort | head -n1|tr "\r" "\n"))

本文出自 “老男孩linux培训” 博客，请务必保留此出处http://oldboy.blog.51cto.com/2561410/942530