1. A method of operating a content router in a system for routing content requests, comprising: receiving, from a domain name service proxy device, a request for a computer address of a second content server, the request including an extended domain name having a client identifier which identifies a client, the extended domain name obtained from a redirection message selectively provided to the client by a first content server in response to a content request to the first content server from the client; processing the extended domain name to identify the computer address based in part on the client identifier; and sending the computer address to the domain name service proxy device for transmission to the client to access content at the second content server.