After a client connects to the Web server, the server only waits for an HTTP request for this many seconds before closing the connection. Browsers tend to send requests immediately, so a small number will do. Choosing a truely enormous number could cause problems. When a computer crashes or its network connection fails due to an external cause, it fails to ask the Web server to reclaim the connection. If about a thousand of these hung connections accumulate without timing out, the Web server can not accept new legitimate connections.