README

Open.NAT

Open.NAT is a lightweight and easy-to-use class library to allow port forwarding in NAT devices that support UPNP (Universal Plug & Play) and/or PMP (Port Mapping Protocol).

Goals

NATed computers cannot be reached from outside and this is particularly painful for peer-to-peer or friend-to-friend software. The main goal is to simplify communication amoung computers behind NAT devices that support UPNP and/or PMP providing a clean and easy interface to get the external IP address and map ports and helping you to achieve peer-to-peer communication.

• Tested with .NET YES
• Tested with Mono YES

How to use?

With nuget :

Install-Package Open.NAT

Go on the nuget website for more information.

Example

The simplest scenario:

NatUtility.DeviceFound += (sender, args) => {
  Console.WriteLine("It got it!!");
  var ip = await device.GetExternalIPAsync();
  Console.WriteLine("The external IP Address is: " + ip);
};

NatUtility.Initialize();
NatUtility.StartDiscovery();

The following piece of code shows a common scenario: It blocks the execution until it discovers a NAT-UPNP device or fails with Timeout after 10 seconds.

var searching = new ManualResetEvent(false);
var externalIP = IPAddress.None;
NatUtility.PortMapper = Upnp; // search only Upnp devices
NatUtility.DiscoveryTimeout = 10*1000; // ten seconds
NatUtility.DiscoveryTimedout += (sender, args) => searching.Set();
NatUtility.DeviceFound += (sender, args) => {
  Console.WriteLine("It got it!!");
  ip = await device.GetExternalIPAsync();
  searching.Set();
};

NatUtility.Initialize();
NatUtility.StartDiscovery();
searching.WaitOne();

For more info please check the Wiki

Documentation

• Why Open.NAT? Here you have ten reasons that make Open.NAT a good candidate for you projects
• Visit the Wiki page

Development

Open.NAT is been developed by Lucas Ontivero (@lontivero). You are welcome to contribute code. You can send code both as a patch or a GitHub pull request.

Here you can see what are the next features to implement. Take it a look! Build Status

Version 2.0.0

• Thus version breaks backward compatibility with v1.
• Changes the event-based nature of discovery to an asynchronous one.
• WANIPConnection v2 supported
• Notifies about lost devices, reconnects and reapplies lost mappings.
• Mappings can be renewed and/or closed on exit depending on how thery were configured.
• Tracing implemented with correlation numbers

Version 1.1.0

• Fix for SSDP Location header.
• After this version Open.NAT breaks backward compatibility.

Version 1.0.19

• Minor changes previous to v2.

Version 1.0.18

• Discovery timeout raises an event.
• Permanent mappings are created when NAT only supports that kind of mappings.
• Protocol to use in discovery process can be specified.
• Automatic renew port mappings before expiration.
• Add operations timeout after 4 seconds.
• Add parameters validation in Mapping class.
• Fix UnhandledException event was never raised.

Version 1.0.17

• Discovery timeout added.
• Auto release ports opened in the session.
• Fix NextSearch to use UtcNow (also performance)
• Fix LocalIP property after add a port.
• Tracing improvements

Version 1.0.16

• Discovery performance and bandwidth improved
• Tracing improved
• Cleaner code