1. A system for optimizing server selection for clients from among a plurality of servers in a packet communication network, the system comprising: a plurality of servers for alternatively responding to client requests; a central server that maintains server selection weights, and, based on the weights, provides in response to a client request a candidate server list of at least two candidate servers to a network node, other than the central server, adapted to interrogate individual servers represented in the candidate server list, the central server receiving feedback from the interrogated individual servers indicating service by the individual servers in response to client requests and modifying the server selection weights based on the feedback, the central server adds to the candidate server list an extra candidate server; wherein the extra candidate server is randomly selected; and wherein a number of servers in the candidate server list, including the candidate servers and the extra, randomly selected, candidate server, is a fixed percentage or a fixed number beyond the number of servers selected based on the weights.