1. A method, in a data processing system, for filtering requests and server responses, the method comprising: configuring a viewport server with filtering rules for responses from a directory server that maintains a collection of data that is accessible via a directory access protocol, wherein the responses are generated to fulfill requests from a client application, wherein the viewport server communicates with the directory server on behalf of the client application using the directory access protocol, wherein the filtering rules determine which data is to be forwarded to the client application, wherein the viewport server comprises a plurality of viewports, wherein each of the plurality of viewports is configured with a respective set of filtering rules for responses from the directory server, and wherein the filtering rules respectively associated with a first viewport and a second viewport within the plurality of viewports provide different types of filtering and determine which data is to be forwarded to respective client applications in a plurality of client applications coupled to the first viewport or the second viewport independent of the client application or a user using the client application; intercepting one or more responses from the directory server to the client application; filtering the one or more intercepted responses according to the filtering rules to produce a set of filtered responses; and sending the set of filtered responses to the client application.