查看远端的端口是否通畅3个简单实用案例

转载

A王瑞江A 2017-03-09 08:24:59 博主文章分类：Linux-shell

文章标签 检查端口 文章分类 服务器

考试题十三：如何查看远端的服务是否开通tcp 8000端口，比如，查看etiantian.org是否开通tcp 8000端口?

解答：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 80

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 80|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 80

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

80/tcp open http

Nmap finished: 1 IP address (1 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：

26 PORT_COUNT=`nmap $ip_add -p $port|grep open|wc -l`

29 [[ $PORT_COUNT -ge 1 ]] && echo "$ip_add $port is ok." || echo "$ip_add $port is unknown."

法三：通过nc命令检查

[root@oldboy ~]# nc -w 5 211.100.98.99 80 && echo ok

[root@oldboy ~]# nc -w 10 8.8.8.8 53 && echo ok ||echo no

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=$1
export oldboyTimestampMemcachedPort=$2
export oldboyTitle=NAGIOS
export oldboyTimestampMD5=4ED06F8D41B9264OLD0BOY30BE5212BB7E34
export wwwServerIp=$3
export wwwServerPort=$4

printf "delete $oldboyTimestampMD5\r\n" | nc $oldboyTimestampMemcachedIp $oldboyTimestampMemcachedPort >/dev/null 2>&1
sleep 1
judge=($(printf "HEAD /oldboy/$oldboyTitle HTTP/1.1\r\nHost: $5\r\n\r\n" | nc $wwwServerIp $wwwServerPort | head -n1|tr "\r" "\n"))