In today's world, almost all of the e-commerce websites or applications are available over the Internet. Such websites are often faced with incoming load of requests that exceeds their capacity, i.e. they are subjected to overload. Most existing web servers show severe drop in throughput and thus degraded performance at high overload. The paper suggests a proxy based overload control mechanism, which uses the drop in throughput relative to arrival rate as an indicator of overload. On overload detection, a self-clocked admission control is activated, which admits a new request only when a successful reply is observed to be leaving the server system.