Page 11 : HTTP Error 405

HTTP Error 405 Method not allowed

Introduction

The HTTP protocol defines methods to indicate the action to be performed on the Web server for the particular URL resource identified by the client (e.g. your Web browser ). The methods are as follows:

• OPTIONS: Find out the communication options available for a particular URL resource. Allows the client to determine the options and/or requirements associated with a resource, or the capabilities of a server, without a specific action involving transfer of data.
• GET: Retrieve the information identified by the URL resource e.g. GET a particular Web page or image. The most common method by far.
• HEAD: Identical to GET except that the server returns header information only, not the actual information identified by the URL resource. Useful to obtain metainformation about the entity implied by the request without transferring the entity-body itself. Often used to test hypertext links for validity, accessibility, and recent modification.
• POST: Submit data to the Web server such as 1) post a message to a bulletin board, newsgroup or mailing list, 2) provide input data - typically from a CGI form - to a data-handling process, 3) add a record directly to a database.
• PUT: Set (place/replace) the data for a particular URL to the new data submitted by the client. For example, upload a new Web page to a server.
• DELETE: Remove the data associated with the URL resource. For example, delete a Web page.
• TRACE: Run a remote, application-layer loop-back of the request message. Effectively a 'ping' which tests what data the Web server is receiving from the client.
• CONNECT: Reserved for use with tunneling (e.g. SSL) via a proxy server. This method is defined only for HTTP version 1.1, not the earlier version 1.0.

All Web servers can be configured to allow or disallow any method.

405 errors in the HTTP cycle

Any client (e.g. your Web browser or our CheckUpDown robot) goes through the following cycle:

• Obtain an IP address from the IP name of the site (the site URL without the leading 'http://'). This lookup (conversion of IP name to IP address) is provided by domain name servers (DNSs).
• Open an IP socket connection to that IP address.
• Write an HTTP data stream through that socket.
• Receive an HTTP data stream back from the Web server in response. This data stream contains status codes whose values are determined by the HTTP protocol. Parse this data stream for status codes and other useful information.

This error occurs in the final step above when the client receives an HTTP status code that it recognises as '405'.

Fixing 405 errors - general

405 errors often arise with the POST method. You may be trying to introduce some kind of input form on the Web site, but not all ISPs allow the POST method necessary to process the form.
All 405 errors can be traced to configuration of the Web server and security governing access to the content of the Web site, so should easily be explained by your ISP.