¿Qué significan los códigos de error?

100 - Informativos
-100 Continue
-101 Switching Protocols

200 - Petición de Cliente Exitosa
-200 OK
-201 Created
-202 Accepted
-203 Non-Authoritative Information
-204 No Content
-205 Reset Content
-206 Partial Content

300 - Petición de Cliente Redirigida
-300 Multiple Choices
-301 Moved Permanently
-302 Moved Temporarily
-303 See Other
-304 Not Modified (El archivo se cargó del cache del navegador en lugar de ser reenviado por el servidor)
-305 Use Proxy

400 - Petición de Cliente Incompleta
-400 Bad Request
-401 Unauthorized
-402 Payment Required
-403 Forbidden
-404 Not Found 405 Method Not Allowed
-406 Not Acceptable
-407 Proxy Authentication Required
-408 Request Time-Out
-409 Conflict
-410 Gone
-411 Length Required
-412 Precondition Failed
-413 Request Entity Too Large
-414 Request-URL Too Large
-415 Unsupported Media Type

500 - Errores del Servidor
-500 Server Error
-501 Not Implemented
-502 Bad Gateway
-503 Out of Resources
-504 Gateway Time-Out
-505 HTTP Version not supported