According to the present invention, methods, apparatus, and computer readable medium are disclosed for defining a virtual domain in an electronic messaging system are disclosed. A virtual domain node is defined that corresponds to a real (non-virtual) domain. The virtual domain node resided in a hierarchically organized directory. A plurality of virtual domain attributes are then assigned to the virtual domain node. The directory is a tree based hierarchical directory arranged in such a way even in a multiple domain environment, a name search operation is executed as if in a flat name space.