US Patent 9634994 Custom responses for resource unavailable errors

A proxy server receives from a client device a request for a network resource hosted at an origins server for a domain. The request is received at the proxy server as a result of a DNS request for the domain resolving to the proxy server. The origin server is one of multiple origin servers that belong to different domains and resolve to the proxy server and are owned by different entities. The proxy server requests the network resource from the origin server. The proxy server receives a response from the origin server that indicates that the network resource is unavailable. The proxy server transmits a custom error page to the client device that indicates that the requested resource is unavailable.