怎麼在Linux伺服器上測試TCP/UDP端口的連通性？

翻譯自：

How to Test Port[TCP/UDP] Connectivity from a Linux Server (文檔 ID 2212626.1)

适用于：

Linux OS - Version Oracle Linux 5.0 to Oracle Linux 6.8 [Release OL5 to OL6U8]

Information in this document applies to any platform.

目标：

在Linux伺服器上檢查TCP/UDP端口的連通性。

解決方案：

telnet和nc 是用來測試端口連通性的一般工具。

telnet可以測試tcp端口的連通性。

nc可以測試tcp和udp端口的連通性。

請確定telnet和nc工具已經安裝

# yum install nc
# yum install telnet
           

測試tcp端口的連通性：

文法如下：

telnet <hostname/IP address> <port number>
           

如下是連通成功的例子：

# 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.

           

如下是連通不成功的例子：

# 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指令來測試tcp端口的連通性：

文法：

nc -z -v <hostname/IP address> <port number>
           

如下是連通成功的例子：

# nc -z -v 192.118.20.95 22
Connection to 192.118.20.95 22 port [tcp/ssh] succeeded!
           

如下是連通不成功的例子：

# 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指令來測試udp端口的連通性：

文法：

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!