HTTP 502 Error – Gateway error (Bad Gateway)

Source: Internet
Author: User
Tags domain name server browser cache

introduce

A server (not necessarily a WEB server) is being used as a gateway or proxy to fulfill a request from a customer (such as your browser or our Checkupdown robot) to access the desired URL. To complete the request, this server accesses an upstream server but receives an invalid response.

This usually does not mean that the upstream server is closed (no response to the gateway/proxy), but that the upstream server and the gateway/proxy are inconsistent on the protocol for exchanging data. Since the Internet protocol is fairly clear, it often means that one or both of these machines are programmed incorrectly or incompletely.

502 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.

This error is generated in the last step described above, when the client receives an HTTP status encoding and recognizes it as a ' 502 ' error.

Resolve 502 Errors-General method

This problem is caused by bad IP traffic between the back-end computers and may include the Web server of the Web site you are trying to access. Before you analyze this problem, you should completely clear the browser cache.

If you surf the web and all the sites you try to visit will look at this problem, then not 1 your Internet service provider (ISP) is having a major device failure/overload, or 2 your internal Internet connection has problems, such as your firewall not running correctly. In the first case, only your ISP can help you. In the second case, you will need to resolve any problems that prevent you from accessing the Internet.

If you encounter this problem only in some sites, it is likely that the problems of these sites, such as one of their devices fail/overload. Please contact the people at these sites.

Resolve 502 Error –checkupdown

The use of proxies and caches on the network is growing. Although we checkupdown robots will always try to ' drill into ' the real Hing of your website, our HTTP requests actually fall out of our control. As long as one of the links in a series of computers dealing with our HTTP requests is broken, a mistake like 502 is easy to produce.

Whenever you encounter a 502 error, please contact us (preferably via email)-You cannot resolve such errors yourself. We must contact your Internet service provider (ISP) and the WEB Server software vendor so that they can check the flow of IP data between different computers under their control.

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