WindyDNS

WindyDNS is a Windows console DNS server that always reply to any DNS queries with a user-specified IP address. It is usually used for simulating a multiple machines or network nodes environment in a single machine. Such mock-up environments are common in software development, testing, and malware analysis.

WindyDNS is based on and adapted from Sam Trenholme's NanoDNS -- a DNS server written for Linux/Unix with remarkably short codes with 538 characters in 14 lines. The focus is on creating a working DNS server with the shortest codes possible.

WindyDNS differs from NanoDNS in the following ways:

• Ported to use Windows Socket (WinSock) API
• Tested to build with MinGW/Microsoft Visual C++ compiler
• Added CMake build system support for wider compiler support
• Retains compatibility with GNU C compiler on Linux/Unix environment
• Much longer with added comments and renamed variables to aid understanding i.e. brevity and keeping the codes short is not the focus

Tip

While WindyDNS is primarily a Windows DNS server, care is taken to ensure compatibility is retained such that it still builds and runs fine on Linux/Unix with the GCC compiler.

Building WindyDNS

WindyDNS uses the CMake build system.

In the WindyDNS source directory:

mkdir build
cd build

CMake allows the use of various build tools. Common ones include the traditional GNU make, and the newer Ninja.

MinGW

To use MinGW:

cmake -G "MinGW Makefiles" ..
mingw32-make

Visual C++

To use Microsoft Visual C++:

cmake -G "NMake Makefiles" ..
nmake

Visual Studio

To use Microsoft Visual Studio 17 2022:

cmake -G "Visual Studio 17 2022" -A Win32 ..
msbuild

Ninja

To use Ninja:

cmake -G Ninja ..
ninja

GNU make

To use standard Unix makefile:

cmake -G "Unix Makefiles" ..
make

The built executable binary windydns.exe will be in the build directory, or for multi-configuration build in Visual Studio either in build\Release or build\Debug sub-directory.

Using WindyDNS

WindyDNS always bind to 0.0.0.0. There is no way to change this currently.

To run, specify the fake IP address to be returned for all DNS queries as a command line argument.

windydns.exe <IP Address>

Example: To make WindyDNS always return 123.234.123.234, run:

windydns.exe 123.234.123.234