【检测远程主机端口是否监听的几种方式】

1.nc

命令格式：nc [-options] [HostName or IP] [PortNumber]

Example:

nc -zvw3 192.168.1.8 22
Connection to 192.168.1.8 22 port [tcp/ssh] succeeded! -- 主机的80端口处于监听状态
nc -zvw3 192.168.1.95 22
nc: connect to 192.168.1.95 port 22 (tcp) failed: Connection refused --主机的80端口未开放

2.nmap

命令格式：nmap [-options] [HostName or IP] [-p] [PortNumber]

Example：

nmap 192.168.1.8 -p 22
......
22/tcp open ssh -- 主机的22端口处于监听状态
nmap 192.168.1.8 -p 80
......
80/tcp closed http -- 主机的22端口未开放

3.telnet

命令格式：telnet [HostName or IP] [PortNumber]

Example：

telnet 192.168.1.9 22
......
Connected to 192.168.1.9. --主机22端口开放

telnet 192.168.1.9 80
Trying 192.168.1.9...
telnet: Unable to connect to remote host: Connection refused --主机80端口未开放