Ubuntu view port usage

1. Use the netstat command

netstat (network statistic) is a command-line tool that can be used to view network-related operating status, including network connections, routing tables, interface status, and more. In Ubuntu, you can use the following command to check the port usage:

$ netstat -tuln

The parameters of this command are explained as follows:

• -t: Indicates that only the connection of the TCP protocol is displayed
• -u: Indicates that only UDP protocol connections are displayed
• -l: Indicates that only the connections that are being listened to are displayed
• -n: Indicates that the domain name is not displayed, but the IP address is displayed directly

After the command is executed, it will output a result similar to the following:

Active Internet connections (only servers)
Proto Recv-Q Send-Q Local Address           Foreign Address         State      
tcp        0      0 0.0.0.0:22              0.0.0.0:*               LISTEN     
tcp6       0      0 :::22                   :::*                    LISTEN     
udp        0      0 127.0.0.53:53           0.0.0.0:*                          
udp        0      0 0.0.0.0:68              0.0.0.0:*                          
udp        0      0 0.0.0.0:5353            0.0.0.0:*                          
udp6       0      0 :::5353