C# Email Server (CSES)

The C# Mail Server is a C# port of the Java Email Server (JES). JES is an established email server targeted at small centrally maintained installations. The C# Mail Server runs on Windows .NET 1.1 and Mono.
CSES is a project to provide the same feature set to the .NET platform. However, in addition to the features of JES, CSES provides individual reusable components that other applications can use to provide email functionality.

Go to http://www.ericdaugherty.com/dev/cses/

See also these related projects.