HTTP Codes

204 No Content

The 204 status code means that the request was received and understood, but that there is no need to send any data back.

301 Moved permanently

Your Web server thinks that your URL has been permanently redirected to another URL. The client system is expected to immediately retry the alternate URL.

302 Moved temporarily

Your Web server thinks that your URL has been temporarily redirected to another URL. The client system is expected to immediately retry the alternate URL.

304 Not Modified

This does not really indicate an error, but rather indicates that the resource for the requested URL has not changed since last accessed or cached.

410 HTTP Error Gone

A 410 status code is returned if the new address is altogether unavailable or the server admin does not want to reveal it.

Upon receiving a 410 status code, the client should not request the resource again in the future.

Clients such as search engines should remove the resource from their indexes.

The requested resource is no longer available at the server and no forwarding address is known. This condition is expected to be considered permanent.

Clients with link editing capabilities SHOULD delete references to the Request-URI after user approval.

If the server does not know, or has no facility to determine, whether or not the condition is permanent, the status code 404 Not Found SHOULD be used instead.

500 Internal server error

The Web server (running the Web Site) encountered an unexpected condition that prevented it from fulfilling the request by the client (e.g. your Web browser or our CheckUpDown robot) for access to the requested URL.

This is a ‘catch-all’ error generated by the Web server.

Basically something has gone wrong, but the server can not be more specific about the error condition in its response to the client.

In addition to the 500 error notified back to the client, the Web server should generate some kind of internal error log which gives more details of what went wrong.

It is up to the operators of the Web server site to locate and analyse these logs.

502 Bad Gateway

A server (not necessarily a Web server) is acting as a gateway or proxy to fulfil the request by the client (e.g. your Web browser) to access the requested URL.

This server received an invalid response from an upstream server it accessed to fulfil the request.

This usually does not mean that the upstream server is down (no response to the gateway/proxy),

but rather that the upstream server and the gateway/proxy do not agree on the protocol for exchanging data.

Given that Internet protocols are quite clear, it often means that one or both machines have been incorrectly or incompletely programmed.

504 Gateway Timeout

504 gateway timeout is a server error code that is received when serving as a proxy or gateway server.

This typically means that it does not receive adequate responses from an upstream server that was specified in the URL.

Such as LDAP, FTP, HTTP, or other forms of auxiliary servers that are needed to have access to in order to finish the request being made of it

509 Bandwidth Limit Exceeded

This status code, while used by many servers, is not specified in any RFCs.