Here is a command that lists all open ports on your system, and lets you know which applications opened them
# List all open ports and the processes that opened them lsof -i -P -n | grep LISTEN
The output typically looks like this
COMMAND | PID | USER | File Descriptor # | IP Type | Device # | File Offset | Protocol | IP:port (LISTEN) |
Sometimes the “COMMAND” column is not enough for you to know which process is listening to a particular port. In this case, use the command below to get more details
# Example: find out more about the process with PID 26123 ps fax | grep 26123
More details about the lsof options
lsof lists all open files and the processes that opened them:
- -i selects both IPV4 and IPV6 addresses
- -P displays the port number instead of the name of the port
- -n displays the actual IP address instead of the host name