To allow more non-enterprise communication endpoints to communicate without having to allocate an extension for every non-enterprise communication endpoint, a request is received to communicate with an enterprise communication system from a non-enterprise communication endpoint. A temporary password is associated with a dynamic communication address (e.g., from a group of dynamic extensions). The temporary password and the dynamic communication address are sent to the non-enterprise communication endpoint. The non-enterprise communication endpoint registers with the communication system using the temporary password and the dynamic communication address. A communication session is established between the non-enterprise communication endpoint and an enterprise communication endpoint using the dynamic communication address. The temporary password is then disassociated from the dynamic communication address, thus freeing up the dynamic communication address for use with another non-enterprise communication endpoint.