Our server library and framework software suite and Apps have been running cross-platform for several years and with the support of .NET Core 2.0 they now run fast and flawlessly on Linux which is a very popular deployment target for our Customers, in fact all our .NET Core Live Demos were developed on Windows and deployed to and running on Linux:
Each project can also be opened and developed on Linux or Mac with VS Code or Rider. Xamarin's solutions has been making C# a popular language for developing native high-performance iOS/Android Apps for several years and the stigma of C# server apps being confined to Windows should be eradicated with the advent of .NET Core.