Abstract: A method and a computer system for transferring data between a first end point and a second end point in a network. The first end point has access to one or more communication servers for sending data and the second end point is represented by one or more communication addresses associated with one or more communication servers for receiving data. One or more communication addresses representative of the second endpoint is received at the first end point. It is then determined whether at least one of the received communication addresses is associated with at least one communication server to which the first endpoint has access. If a positive determination is made, data is transmitted from the first end point using a selected communication server to which the first end point has access and a communication address representing the second end point and associated with said selected communication server.