# See Open Network Connections


To quickly see the open network connections, use the `lsof` command.

```command
sudo lsof  -T -i -n
```

* `-T` specifies that the output should include TCP  information. This option can take  arguments to specify what type of TCP  information to include:

  * `-T f`: Includes file descriptor information.
  * `-T info`: Includes information about the TCP state, like `ESTABLISHED` or `LISTENING`.
  * `-T text`: Includes the TCP state in text form, like `ESTABLISHED` or `SYN_SENT`.

  Without additional arguments, it shows the TCP state.

* `-i`: Lists information about network files, such as network connections.

  * `-i4`: Shows only IPv4 network connections.
  * `-i6`: Shows only IPv6 network connections.

  Without additional arguments, it shows all network connections.

* **`-n`**: Prevents conversion of IP addresses to host names, port numbers to service names, and user IDs to user names. This makes the command run faster and avoids DNS lookups.

Adding the `-r` switch will refresh the results:

```command
sudo lsof  -T -i -n -r
```

Press `CTRL+C` to return to your prompt.