Seeing what services are open on your ports on your system is a useful tool for system administrators, becaues of this most linux flavours have a built in system to check, a tool called lsof. Below is a list of what all of the headers within the command mean in the context of networking
| Header | Description |
|---|---|
| Command | Lists the running service by its name |
| PID | The process ID of the service |
| User | Which user on the system is running that service |
| FD | File Descriptor - What permissions the process has |
| Type | What type of service is running |
| Device & Size/Off | The disk file size in use |
| Node | The traffic type in use |
| Name | The devices name as well as it's listen status |
More information can be found on the use of lsof by using the following command;
man lsof
Before carrying out any commands please make sure you are logged into a privileged or superuser account.
Showing all services on open ports
lsof -i
Searching for services on a specific port
lsof -I :PORT
Closing a process by port
kill $(lsof -t -i:PORT)
Closing a process by PID
kill PID
