204 is the fastest, since it is exactly zero bytes of content. For most webservers you don't even need to point it at a specific file, just say "return 204" and

204 is the fastest, since it is exactly zero bytes of content. For most webservers you don't even need to point it at a specific file, just say "return 204" and that's enough. I've done this numerous times to "whitehole" bad scanners or bots with great success :)