1. curl

curl：该命令可视为不带参数的GET请求。

  • 命令格式
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curl 服务地址
  • 操作示例
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[root@VM-0-9-centos tmp]# curl http://localhost:80
<!DOCTYPE html>
<html>
<head>
<title>Welcome to nginx!</title>
<style>
    body {
        width: 35em;
        margin: 0 auto;
        font-family: Tahoma, Verdana, Arial, sans-serif;
    }
</style>
</head>
<body>
<h1>Welcome to nginx!</h1>
<p>If you see this page, the nginx web server is successfully installed and
working. Further configuration is required.</p>

<p>For online documentation and support please refer to
<a href="http://nginx.org/">nginx.org</a>.<br/>
Commercial support is available at
<a href="http://nginx.com/">nginx.com</a>.</p>

<p><em>Thank you for using nginx.</em></p>
</body>
</html>
[root@VM-0-9-centos tmp]# 

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[root@VM-0-9-centos tmp]# curl http://localhost:8080
curl: (7) Failed connect to localhost:8080; Connection refused

2. netstat

netstat ：监听端口状态

  • 命令格式
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netstat 参数 | grep 端口号
  • 参数说明

-a：显示所有socket

-l：显示所有处于监听中的端口

-n：显示本地的IP地址

-p：显示pid及进程名称

-t：只显示tcp端口

-u：只显示udp端口

  • 操作示例

netstat -ltnp：查询所有处于监听状态的tcp端口

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[root@VM-0-9-centos tmp]# netstat -ltnp
Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State       PID/Program name    
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      3781/nginx: master  
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN      1457/sshd           
tcp        0      0 0.0.0.0:8888            0.0.0.0:*               LISTEN      1455/python

netstat -anp | grep 80：查询所有处于监听状态的tcp端口

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[root@VM-0-9-centos tmp]# netstat -anp | grep 80
tcp        0      0 0.0.0.0:80              0.0.0.0:*               LISTEN      3781/nginx: master  
tcp        0      0 10.0.0.9:42842          169.254.0.55:8080       TIME_WAIT   -                   
tcp        0      0 10.0.0.9:80             170.64.161.204:38658    TIME_WAIT   -                   
tcp        0      0 10.0.0.9:35380          169.254.0.55:5574       ESTABLISHED 5133/YDService      
tcp        0      0 10.0.0.9:80             170.64.161.204:38694    TIME_WAIT   -                   
tcp        0      0 10.0.0.9:80             170.64.161.204:38660    TIME_WAIT   -                   
udp6       0      0 fe80::5054:ff:fead::123 :::*                                657/ntpd            
unix  2      [ ACC ]     STREAM     LISTENING     8005     1/systemd            /run/systemd/journal/stdout
unix  5      [ ]         DGRAM                    8008     1/systemd            /run/systemd/journal/socket
unix  12     [ ]         DGRAM                    8010     1/systemd            /dev/log

3. telnet

telnet：用来探测指定 ip 是否开放指定端口。

在 Linux 环境下 Telnet 是需要安装的。 安装命令：yum install telnet

  • 命令格式
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telnet IP 端口
  • 操作示例
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[root@VM-0-9-centos tmp]# telnet 127.0.0.1 80
Trying 127.0.0.1...
Connected to 127.0.0.1.
Escape character is '^]'.
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[root@VM-0-9-centos tmp]# telnet 127.0.0.1 8080
Trying 127.0.0.1...
telnet: connect to address 127.0.0.1: Connection refused