Field-test to determine the behavior of your NAT-Router (please participate)

[Andreas_Mueller_UNI-TUE]

Hello,

we at the University of Tuebingen are investigating the behavior of Network Address Translation (NAT) with regard to NAT traversal. Today, most households use a Network Address Translator (NAT) integrated into their DSL-Router to connect to the internet. The NAT translates between the public and the private realm and creates a mapping for each outgoing connection. This works well as long as connections are established from the inside because the NAT is aware of all incoming packets and can forward them to the appropriate private host. But as soon as a user wants to provide a service behind a NAT, the NAT is not able to map inbound packets to this host because no state exists for these packets. This problem is called the NAT-Traversal Problem. There are already a number of approaches to solve this problem, but these approaches depend on the NAT behavior.

The implementation of a NAT is not standardized. The behavior of NATs not only varies from vendor to vendor, but also from type to type. To evaluate and test as many NATs as possible, we created a small application that determines the properties of a NAT and makes some connectivity tests with our test server.

Therefore, we kindly ask you to download the NAT-Tester and run it on your home computer. The test takes 1-2 minutes and is done automatically. After the test, you will be directed to an internet-page where you can provide some information about the tested NAT (vendor and model). The test client is available for Windows and Linux. The Source-Code can be found within the Linux package. If you have any questions, please contact us.

Visit NAT-Tester University of Tuebingen - WSI-RI at your convenience to participate and to look at all the results.

Kind Regards
Andreas Mueller and Andreas Klenk

[hazel]

What guarantee do we have that this is on the level? Sorry but I'm paranoid about this sort of thing.

[Andreas_Mueller_UNI-TUE]

You're right, you should always be paranoid about running unknown software on you local machine.

But, you're very welcome to study the source-code of the test-client, which is available on our web-page.

Since we're a public institute (University of Tuebingen (Universität Tübingen)) we are not interested in ruining our reputation, you have to trust us on this one or as said you're welcome to download the source-code.

If you still don't trust us, you might want to run the test within a virtual machine or within a read-only live-linux system.

Kind regards
Andreas Mueller