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NAT32 IP Router

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NAT32® is a versatile IP Router implemented as a WIN32 application with the following features: View within NAT32


The Generic Version is fully functional but unsupported. How to purchase support. [DEPRECATED]

Installation Requirements

NAT32 will run on any Windows 7 (or later) platform. No particular service packs or .NET runtimes are required, nor are any Visual Studio DLLs required.

NAT32 is written entirely in C and statically linked to the Standard C Library. Memory requirements are extremely modest (approx. 2 MB) and network throughput, even on legacy platforms, is outstanding. Click here to test NAT32 Name Resolution performance on your machine.


NAT32 is distributed as a Microsoft Installer package and must be installed to a write-enabled directory. The WinPkFilter Driver that it uses can be installed from within NAT32 with the command: driver install. The full procedure is described here.

If OpenVPN support is required, the TAP-Windows driver must be installed when OpenVPN is installed.

Running NAT32

NAT32 can be started by running the Windows Explorer and then clicking the NAT32.EXE file located in your NAT32 directory (usually C:\NAT32v2). Full details on NAT32 configuration and command-line arguments can be found here.


NAT32 is an unconventional Windows application in that it is structured as a multi-threaded Operating System with integrated support for TCP/IP networking. It has its own TCP/IP stack as well as a device interface to the host system's TCP/IP stack (usually Winsock). This dual-stack architecture allows great flexibility in IP routing and several unique network configurations can thus be supported.

NAT32 is the only IP router of its kind that can route packets based on their source address, destination prototol, destination port, interface utilization, and (of course) destination IP address. Simultaneous use of multiple Internet connections thus becomes possible, a feature that is not available in any version of Windows to date.

NAT32 has its origins in a PC port of Douglas Comer's Xinu Operating System. A product called NAT95 for PC-compatible systems was published in late 1994. It was one of the first NAT-capable IP Routers ever to be released. Microsoft Corporation embraced the NAT technique many years later (April 23, 1999) in Windows 98SE, calling it Internet Connection Sharing.

NAT32 Version 2 was designed to provide connection sharing features primarily for Windows 7 Starter Edition, as Microsoft chose to disable that feature in that version of Windows.

NAT32 Version 2 is documented in a series of web pages and at


Many thanks go to the University of Canberra, Australia for kindly supporting the development of NAT32 Version 2.

Thanks go also to the many users who have tested NAT32 over the years and provided valuable feedback on all aspects of the software, as well as many great ideas and suggestions.

And finally, many thanks go to the father of Xinu, Professor Douglas Comer, for his inspirational work in the fields of Operating Systems and Internetworking.

Xinu License

Email Support

Because the original NAT32 Support email address is well known to spammers around the world, it will change on January 1, 2009 (and at random intervals thereafter). You can always obtain support by clicking here.

System Information

© 1995-2023 NAT32® is a trademark of NAT Software, Australia. ABN