telnet和nc 是用来测试端口连通性的一般工具。
telnet可以测试tcp端口的连通性。
nc可以测试tcp和udp端口的连通性。
请确保telnet和nc工具已经安装
# yum install nc
# yum install telnet
测试tcp端口的连通性:
语法如下:
telnet <hostname/IP address> <port number>
如下是连通成功的例子:
# telnet 192.118.20.95 22
- Trying 192.118.20.95…
- Connected to 192.118.20.95.
- Escape character is ‘^]’.
- SSH-2.0-OpenSSH_6.6.1
- Protocol mismatch.
- Connection closed by foreign host.
- 如下是连通不成功的例子:
- # telnet 192.118.20.95 22
- Trying 192.118.20.95…
- telnet: connect to address 192.118.20.95: No route to host
使用nc命令来测试tcp端口的连通性:
语法:
nc -z -v <hostname/IP address> <port number>
如下是连通成功的例子:
- # nc -z -v 192.118.20.95 22
- Connection to 192.118.20.95 22 port [tcp/ssh] succeeded!
如下是连通不成功的例子:
- # nc -z -v 192.118.20.95 22
- nc: connect to 192.118.20.95 port 22 (tcp) failed: No route to host
使用nc命令来测试udp端口的连通性:
语法:
nc -z -v -u <hostname/IP address> <port number>
- # nc -z -v -u 192.118.20.95 123
- Connection to 192.118.20.95 123 port [udp/ntp] succeeded!