What's the difference between ASP.NET Full Trust and Medium Trust?

Microsoft’s ASP.NET web technology / language allows us to define trust levels, which dictate what operations are permitted by ASP.NET applications. A web hosting company can either use one of the preset trust levels - Full, High, Medium, Low, or Minimal - or can create a custom trust level.

Full trust is the default, allows ASP.NET applications to execute native code, to read from the Registry and Windows Event Log, and to read and write to files outside of the application’s virtual directory. In short, with full trust one web application could delete the entire contents of another web application.

Now most web hosting companies run in medium trust, which greatly reduces the potential for harm by limiting the set of operations an ASP.NET application can perform. But Medium trust will place a number of restrictions on an application, including limiting an application’s file access to within the virtual directory where the application lives. While the protection granted by medium trust is reassuring, its limited functionality can be a cause of worry for developers. There are a lot of web applications and components in the market which do require full trust to work as desired.

Now what will happen, in this scenario. In this case a lot of web hosts run the web applications as modified full trust, which is a modified version of full trust and web hosting companies block certain modules or permissions of full trust. e.g. you can change this full trust to be effective only for the needed functionality (or vice versa, disable it for the File IO). This can be done through the .NET Framework Configuration tools on the server (caspol.exe etc) but it will require some additional setup.

HostBuddy.com provides our customer both Modified Full Trust and Medium Trust server. You can contact our support to set this up according to your needs.