Summary of HTTP status code summarization and problem experience

We often encounter 404, 500, 302 and other hints, what exactly do they mean? In addition to these common status codes, what are some of the possible status codes that we have not encountered yet? Here I made a summary, share with you.

Common HTTP errors can be categorized into the following four categories. Each class is subdivided into many small errors. When you do not open the site or open the site error, first check whether you entered the site is wrong, check the network is a problem or whether DNS can be resolved. Check the following HTTP common error analysis when you are sure there are no problems:

1, 400 error
Cause of the problem:
The page you are trying to open does not exist or the authentication information you have filled in is incorrect.
Workaround:
Re-attempt still error after submitting work order.

2, 401 Error
The most common error hint: 401 Unauthorized
Cause of the problem:
The Web site returned an HTTP 401 error when you tried to access a restricted page without authorization. A bad logon attempt is the main cause of this error.
Workaround:
Contact the webmaster to get the correct account.
Submit Work order contact technician for processing.

3, 403 error
The most common error hint: 403 FORBIDDEN
Cause of the problem:
Usually the site is not bound to the default home page or binding default home page error.
Workaround:
You check the default home page of your program, add the default home page in the background.

4, 404 error
The most common error hint: 404 Not FOUND
Cause of the problem:
When you open a Web site, you cannot find the file you requested (that is, the Web page), the file may be moved to another location, or it will not exist at all.
Solution:
(1) Please log in to FTP to check whether the file or webpage does not exist, to restore the missing Web files to the correct location.
(2) Submit a ticket to recover your data for one day of the week.

5, 500 error

The most common error hint: SERVER error
Cause of the problem:
(1) The server side of the web design is problematic and the server does not open detailed error prompts.
Workaround:
(1) Download the program to local, then check the program, upload the complete correct website program.
(2) Submit work order contact Technician to handle.

6, 503 Error

Cause of the problem
The application pool is closed or traffic is exhausted due to incompatible program configuration.
Workaround:
(1) The Linux virtual host can be restored to normal by restarting the site in the background. If not, please submit a ticket.
(2) Widows Virtual Host please submit work order Contact Technician.

HTTP Status Code Summary description
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Success 2XX successfully processed the requested status code.
200 the server has successfully processed the request and provided the requested Web page.
204 The server successfully processed the request, but did not return any content.
REDIRECT 3XX use redirects in each request no more than 5 times.
301 The requested page has been permanently moved to a new location. When URLs change, use 301 code. The new URL is saved in the Search engine index.
302 The requested Web page is temporarily moved to a new location. The original URL is saved in the Search engine index.
304 If the page has not been updated since the requestor last requested it, use 304 code to tell the search engine robot that it saves bandwidth and overhead.
Client Error 4XX indicates a possible error in the request and prevents the server from processing.
400 the server does not understand the syntax of the request.
403 The server denied the request.
404 the server could not find the requested Web page. Pages that do not exist on the server often return this code.
410 after the requested resource is permanently deleted, the server returns this response. This code is similar to the 404 (not Found) code.
However, in the case where the resource existed before and now does not exist, it is sometimes used to replace the 404 code. If the resource has been permanently deleted, you should use 301 to specify a new location for the resource.
Server error 5XX indicates that an internal error occurred while the server was processing the request. These errors may be the error of the server itself, not the request.
500 the server encountered an error and could not complete the request.
503 servers are not currently available (due to overloading or downtime maintenance). Typically, this is only a temporary state.

Detailed decomposition:

2XX success

200 normal; The request is complete.
201 Normal; Immediately after the POST command.
202 normal; Accepted for processing, but processing is not yet complete.
203 normal; Part of the information-the returned information is only part of it.
204 normal; No response-the request has been received, but there is no information to echo back.

3XX redirection

301 Moved-The requested data has a new location and the change is permanent.
302 found-The requested data temporarily has a different URI.
303 See other-the response to the request can be found under another URI, and the response should be retrieved using the GET method.
304 unmodified-The document was not modified as expected.
305 using a proxy-the requested resource must be accessed through the proxy provided in the Location field.
306 unused-no longer in use; Keep this code for future use.

Errors that occur in the 4XX client

400 Error request-There is a syntax problem in the request, or the request cannot be satisfied.
401 Unauthorized-The client is not authorized to access the data.
402 Payment required-Indicates that the billing system is valid.
403 Forbidden-access is not required even with authorization.
404 Not Found-the server cannot find the given resource; The document does not exist.
407 Proxy authentication Request-The client must first use the proxy to authenticate itself.
415 media type is not supported-the server denies the service request because the format of the requested entity is not supported.

Errors that occur in the 5XX server

500 INTERNAL Error-the server could not complete the request because of an unexpected situation.
501 not executed-the server does not support the requested tool.
502 Error Gateway-server received an invalid response from the upstream server.
503 Unable to get service-the server cannot process the request due to temporary overload or maintenance.

504 Gateway Timeout
When a server acting as a gateway or agent attempts to execute a request, it fails to receive a response from the upstream server (the server that the URI identifies, such as HTTP, FTP, LDAP), or the secondary server (such as DNS).
Note: Some proxy servers return 400 or 500 errors in DNS query timeout

505 HTTP Version not supported
The server does not support or refuses to support the HTTP version used in the request. This implies that the server cannot or does not want to use the same version as the client. The response should contain an entity that describes why the version is not supported and which protocols the server supports.

506 Variant Also negotiates
Extended by the Transparent Content negotiation Protocol (RFC 2295), there is an internal configuration error on behalf of the server: The requested negotiation meta-resource is configured to use itself in transparent content negotiation, so it is not an appropriate focus in a negotiation process.

507 Insufficient Storage
The server cannot store the content necessary to complete the request. The situation is considered to be temporary. WebDAV (RFC 4918)

508 Loop Detected
An infinite loop appears in the server discovery request

509 Bandwidth Limit exceeded
The server reached the bandwidth limit. This is not an official status code, but is still widely used.

510 Not Extended
The policies needed to get resources are not met. (RFC 2774)

How to handle common errors

500 error

500 error is the webmaster often encountered problems, on my experience, causes and solutions are summarized as follows:

1, the number of users running too much, the pressure on the server is too large, the server can not respond, the report HTTP500 error.

This is the main reason why the website reported 500 error, why many websites suddenly reported 500 error (Service unavailable)? 90% is due to excessive space pressure, beyond the limits set by the space quotient.

Encounter this problem, it is best to find the first time the space provider after-sales service, they will generally help you recycle the application pool, the problem will be resolved. If you do not find after-sales service, you can in the space management background, find the "recycling application pool" that project, manually execute it yourself. However, some space management backgrounds do not provide this service.

2, if the possibility of excluding the 1th, then a big reason is the procedural problems.

Can do a simple test page, to see if it can run successfully, and then detect the error page, so that targeted changes.

Where the connection is not made, the HTTP500 error is reported. The problem is solved by manual or auto-correlation.

3, if the operation in the test needs to insert data into the database, if the large amount of data causes the table space in the database is full, or the buffer pool is small can not satisfy the data access, etc., can cause HTTP500 error.

The solution is to adjust the database, modify the connection pool size, and so on, according to individual circumstances to correct.

Summary of HTTP status code summarization and problem experience