A method of processing digital content service requests from one or more user devices in a user network, the user network having a user-network administrator and comprising one or more user devices and at least one control device configured to control communication between the one or more user devices in the user network and one or more servers (16, 18) in one or more external networks, each digital content service request relating to digital content desired by a user of a user device, the method comprising: the at least one control device receiving, via an administrator interface configured to receive policy indications from the administrator of the user network, a policy indication in respect of each of one or more user devices in the user network, the respective policy indications indicating a desired control policy desired by the administrator of the user network to be implemented in respect of digital content service requests from the respective user devices in the user network; the at least one control device associating (s63, s67) respective user device source identifiers (124a, 124b, 125a, 125b) with respective user devices in the user network in respect of which policy indications have been received, each user device source identifier indicating to a server in an external network a network location to which a response to a request should be directed, the user device source identifier associated with a particular user device being dependent on the policy indication received in respect of that user device; and the at least one control device receiving a digital content service request from a user device in the user network, the digital content service request containing an indication of a domain name associated with a content provider from which digital content is desired by the user of the user device, and submitting a server location request (s64, s68) in respect thereof to a domain name system server configured to respond (s66, s69) to respective server location requests in a manner dependent on a user device source identifier included with the server location request, the server location request comprising: - an indication of the domain name indicated in the digital content service request; and - the user device source identifier associated with the user device from which the digital content service request has been received. the at least one control device receiving, via an administrator interface configured to receive policy indications from the administrator of the user network, a policy indication in respect of each of one or more user devices in the user network, the respective policy indications indicating a desired control policy desired by the administrator of the user network to be implemented in respect of digital content service requests from the respective user devices in the user network; the at least one control device associating (s63, s67) respective user device source identifiers (124a, 124b, 125a, 125b) with respective user devices in the user network in respect of which policy indications have been received, each user device source identifier indicating to a server in an external network a network location to which a response to a request should be directed, the user device source identifier associated with a particular user device being dependent on the policy indication received in respect of that user device; and the at least one control device receiving a digital content service request from a user device in the user network, the digital content service request containing an indication of a domain name associated with a content provider from which digital content is desired by the user of the user device, and submitting a server location request (s64, s68) in respect thereof to a domain name system server configured to respond (s66, s69) to respective server location requests in a manner dependent on a user device source identifier included with the server location request, the server location request comprising: - an indication of the domain name indicated in the digital content service request; and - the user device source identifier associated with the user device from which the digital content service request has been received. - an indication of the domain name indicated in the digital content service request; and - the user device source identifier associated with the user device from which the digital content service request has been received.