测试远程端口是否处于监听状态

最新推荐文章于 2024-04-28 13:58:33 发布

转载最新推荐文章于 2024-04-28 13:58:33 发布 · 2.3k 阅读

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原文链接：https://blog.youkuaiyun.com/whatday/article/details/123777461

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#端口

本文介绍了三种检查网络端口是否开放的方法：使用telnet、ssh及wget工具进行连接测试。涵盖不同场景下的具体操作步骤，如telnet连接监听与未监听端口的区别、ssh连接时的调试模式使用等。

1、使用telnet判断

telnet是windows标准服务，可以直接用；如果是linux机器，需要安装telnet.

用法: telnet ip port

1）telnet连接未监听的端口

[root@localhost ~] # telnet 10.0.250.3 80
Trying 10.0.250.3...
telnet: connect to address 10.0.250.3: Connection refused #直接提示连接被拒绝

2）telnet连接监听中的端口

[root@localhost ~] # telnet localhost 22
Trying ::1...
Connected to localhost. #看到Connected就连接成功了
Escape character is '^]' .
SSH-2.0-OpenSSH_5.3
a
Protocol mismatch.
Connection closed by foreign host

2、使用ssh判断

用法: ssh -v -p port username@ip

-v 调试模式(会打印日志).

-p 指定端口

username可以随意

1）ssh连接未监听的端口

[root@localhost ~]# ssh 192.168.1.20 -p 7412
ssh: connect to host 192.168.1.20 port 7412: Connection refused

2）ssh连接监听中的端口

当监听端口不是ssh服务端口时

[root@localhost ~]# ssh 192.168.1.20 -p 9999
ssh_exchange_identification: Connection closed by remote host

当监听端口是ssh服务端口时：

[root@localhost ~]# ssh localhost -p 22
Warning: Permanently added 'localhost' (ECDSA) to the list of known hosts.
root@localhost's password:

会出现输入密码提示

3、使用wget判断

wget是linux下的下载工具，需要先安装.

用法: wget ip:port

1）wget连接未监听的端口

[root@localhost test]# wget 10.0.250.3:80
--2022-03-27 17:43:41--  http://10.0.250.3/
Connecting to 10.0.250.3:80... ^C

一直卡在连接中

2）wget连接监听中的端口

[root@localhost test]# wget localhost:22
--2022-03-27 17:42:48--  http://localhost:22/
Resolving localhost (localhost)... 127.0.0.1, ::1
Connecting to localhost (localhost)|127.0.0.1|:22... connected.
HTTP request sent, awaiting response... 200 No headers, assuming HTTP/0.9
Length: unspecified
Saving to: ‘index.html.2’

    [ <=>                                                                                                                                                ] 40          --.-K/s   in 0s

2022-03-27 17:42:48 (3.62 MB/s) - Read error at byte 40 (Connection reset by peer).Retrying.

--2022-03-27 17:42:49--  (try: 2)  http://localhost:22/
Connecting to localhost (localhost)|127.0.0.1|:22... connected.
HTTP request sent, awaiting response... 200 No headers, assuming HTTP/0.9
Length: unspecified
Saving to: ‘index.html.2’

    [ <=>                                                                                                                                                ] 0           --.-K/s   in 0s


Cannot write to ‘index.html.2’ (Connection reset by peer).