1. A computer-implemented method, comprising: receiving a plurality of first request data; wherein each first request data of the plurality of first request data includes (a) a first identification value and (b) data that identifies a particular LDNS server of one or more LDNS servers; receiving a plurality of second request data; wherein each second request data of the plurality of second request data includes (c) a second identification value and (d) data that identifies a particular client of a plurality of clients; wherein, for each first request data of the plurality of first request data, the first identification value included in the first request data was provided in a request from a client of the plurality of clients to the particular LDNS server identified in the first request data; wherein, for each second request data of the plurality of second request data, the second identification value included in the second request data was provided in a request from the client identified in the second request data to a particular web beacon collection server of one or more web beacon collection servers; wherein each first identification value included in each first request data of the plurality of first request data is different from every other first identification value included in every other first request data of the plurality of first request data; wherein each second identification value included in each second request data of the plurality of second request data is different from every other second identification value included in every other second request data of the plurality of second request data; and for each second request data of the plurality of the second request data, creating and storing mapping data associating the particular client of the plurality of clients identified in the second request data with the particular LDNS server identified in a first request data of the plurality of first request data by identifying the first request data of the plurality of first request data that includes a first identification value that matches the second identification value included in the second request data; wherein the method is performed by one or more computing devices.