总结几种Linux环境下端口状态判断的方法

1. nc命令
语法：nc -z -v -n IPADDRESS port
-z 仅用于端口扫描，0输入输出
-v 显示指令执行过程
-n 直接使用IP地址，而不是通过域名服务器

[root@shansibleqa ~]# nc -z -v -n IP 22 Ncat: Version 7.50 ( https://nmap.org/ncat ) Ncat: Connected to IP:22. Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.

[root@shansibleqa ~]# nc -z -v -n IP 587 Ncat: Version 7.50 ( https://nmap.org/ncat ) Ncat: Connected to IP:587. Ncat: 0 bytes sent, 0 bytes received in 0.01 seconds.

2. wget命令
语法：wget ip:port
如果通

[root@shansibleqa ~]# wget IP:22 --2019-12-24 17:43:50-- http://IP:22/ Connecting to IP:22... connected. HTTP request sent, awaiting response... 200 No headers, assuming HTTP/0.9 Length: unspecified

如果不通

[root@shansibleqa ~]# wget IP:80 --2019-12-24 17:43:56-- http://IP/ Connecting to IP:80... failed: No route to host. 

3. shell命令
语法：ssh -v -p port IP
能够连上

[root@shansibleqa ~]# ssh -v -p 80 XX.XX.XX.XX OpenSSH_7.4p1, OpenSSL 1.0.2k-fips 26 Jan 2017 debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 58: Applying options for * debug1: Connecting to XX.XX.XX.XX [XX.XX.XX.XX] port 80. debug1: Connection established. debug1: permanently_set_uid: 0/0

连不上

[root@shansibleqa ~]# ssh -v -p 23 XX.XX.XX.XX OpenSSH_7.4p1, OpenSSL 1.0.2k-fips 26 Jan 2017 debug1: Reading configuration data /etc/ssh/ssh_config debug1: /etc/ssh/ssh_config line 58: Applying options for * debug1: Connecting to XX.XX.XX.XX [XX.XX.XX.XX] port 23. debug1: connect to address XX.XX.XX.XX port 23: Connection timed out ssh: connect to host XX.XX.XX.XXport 23: Connection timed out

4. curl命令
语法：curl ip:port
端口通

[root@shansibleqa ~]# curl ip:22 SSH-2.0-OpenSSH_7.4 curl: (56) Recv failure: Connection reset by peer 

端口不通

[root@shansibleqa ~]# curl ip:443 curl: (52) Empty reply from server