HTTP 501 Error – not implemented (not implemented)

introduce

Your Web server does not understand or support the HTTP methods it finds in the HTTP data stream sent to it by the client, such as your browser or our Checkupdown robot. These methods are defined in the HTTP protocol as follows: options: Find the communication options that apply to a particular URL resource. Allows clients to determine resource-related options and/or requirements, or the performance of a server, without the need to perform specific actions involving data transfer. Get: Retrieves information determined by the URL resource, such as getting a specific page or picture. This is the most common method. Head (header): In addition to the server feedback header information rather than the information itself determined by the URL resource, basically the same as get (obtain). Can be used to obtain the meta information (metainformation) of the response entity required by a request, without the need to transmit the response entity itself. Often used to test the validity, accessibility, and recent modifications of hypertext links. POST (posting): Submitting data to a WEB server, such as 1, on an electronic bulletin board, newsgroup, or sending a message to a mailing list, 2 provides input data-typically by a common Gateway Interface (CGI) table, to a data processing process, 3) directly adding records to a database. Put (place): Set the data of a specific URL (placed/replaced) into the new data submitted by the customer. For example, upload a new Web page to the server. Delete (delete): Deletes data related to the URL resource. For example, delete a Web page. Trace (Trace): A remote application layer loopback that runs the request information. is actually a ' ping ' to test what data the WEB server is receiving from the client. Connect: reserved for use by proxy servers and tunnels (such as SSL). This method is only defined in HTTP version 1.1, but not in the previous version 1.0.

If the request method in the HTTP data stream is not one of these, it will cause a 501 error. Or the method may be valid, but it is not supported by your WEB server. This usually happens only when a new method is used, and the same WEB server receives the Connect method.

501 errors in the HTTP loop

Any client, such as your browser or our Checkupdown robot, communicates with your network server by looping through the following loops: An IP address is obtained from the IP name of your site (that is, the URL of your site-url, without the start of ' http://'). This correspondence (that is, the correspondence between IP names and IP address conversions) is provided by the Domain name server (DNSS). Open an IP socket (socket) to connect to the IP address. Writes an HTTP data stream through this socket. The HTTP data stream that receives the response from your Web server. The data flow includes a state encoding whose value depends on the HTTP protocol. Resolves the data stream to obtain status codes and other useful information.

The error is generated in the last step described above, when the client receives the HTTP status code and recognizes it as ' 501 '.

Resolve 501 Errors-general method

This error should be very rare in any browser. It is more likely if the client is not a browser-especially if the WEB server is old. In both cases, if the client specifies a valid request type, the Web server either responds incorrectly or needs to be upgraded.