.NET applications operate under a given trust level. Normal desktop applications operate under full trust, while web applications that are hosted in shared environments are normally run under the partial trust level (sometimes known as “medium trust”). Some hosting providers host shared applications in their own app pools and allow the application to run under full trust, but this configuration is relatively rare.

Connector/Net versions prior to 5.0.8 and 5.1.3 were not compatible with partial trust hosting. Starting with these versions, Connector/Net can be used under partial trust hosting that has been modified to allow the use of sockets for communication. By default, partial trust does not include SocketPermission. Connector/Net uses sockets to talk with the MySQL server so it is required that a new trust level be created that is an exact clone of partial trust but that has SocketPermission added.