# Network Connections Viewer

The Network Connections Viewer is a tool which lets you see all currently established TCP connections, and see
on which TCP and UDP ports your computer "listens" for incoming connections.

Seeing what programs open network connections, and to which hosts, can give insights to what's **really**
going on behind the scenes on your computer. Network Connections Viewer is an investigative tool which can
come in handy when you suspect privacy violations by some of your software, or when you suspect infection by a
worm or virus. Seeing what ports are open on your computer can also be important in the evaluation of your
computer's security and protection against hackers.

### Columns

- **Program** - What program opened this network connection or is listening on the network port.
- **Local address and port** - What is the local address and port in an established connection.
- **Remote address and port** - What is the remote address and port in an established connection.
- **Scope** - Self explanatory: is this an Internet or LAN network traffic? Visible only in the "Open TCP
  connections" tab.
- **Sent, Received** - The traffic of this connection since the DU Meter service started, or since it was
  reset on the Options tab. Traffic by program, over any period, is on the Programs tab of
  [DU Meter Totals and Reports](https://www.hageltech.com/support/kb/du/using/totals).
- **Connection state** - There are several pre-defined states in TCP protocol. This column lists the current
  state of the connection. Please refer to TCP documentation for specific meanings of each state.

### Colors

In the "Open TCP Connections" tab, red lines denote Internet traffic, blue represent LAN traffic, and a grey
line means that this connection is in the process of being shut down.

### Options

- **Automatic Refresh Interval** - How often do you wish to refresh the lists. If you have many active
  connections, and your computer is not very fast, you may want to set this parameter to "never" and refresh
  manually, to conserve system resources.
- **Display IP Addresses** - choose whether to display just the host name, IP address only, or both.
- **Display port addresses** - how to display port addresses. Port addresses can be displayed in numerical
  format only, or DU Meter can consult the 'services' file, and show the protocol that uses this port most
  often. DU Meter has a built-in 'services' file, which contains much more data than what is usually present
  on Windows computers. You can opt whether to use this special file or not. Please note that some ports are
  used by different programs for different needs, and DU Meter cannot guess. It simply shows the protocol that
  is used most frequently on that port, but in your specific case this port can be used for something else
  entirely.
- **Reset traffic statistics** - counts the traffic of the connections from zero again. These figures are not
  kept across restarts of the computer in any case.