GetNetGoing helps make networks work
Help for HTTP error 502: “Bad Gateway”This HTTP error occurs when a gateway or proxy1 that exists between you and a server that you are trying to access, received an invalid response from another server that it needed to access (e.g. the website that you are trying to access) in order to fulfill your request. For example, the website that you are trying to access may use a gateway to forward your request to other programs, and if such a program gives an improperly formatted response then the gateway would respond with a HTTP 502 error. error code 0x80244021 (hexadecimal 80244021).
Apache servers report this as:
Microsoft IIS web servers may report this as “502 - Web server received an invalid response while acting as a gateway or proxy.” and may provide the following extended codes that give a more specific reason of the error:
When Twitter is over capacity, it uses a HTTP 502 response to send its “fail whale” error message:
Google servers sometimes report “502 Server Error: The server encountered a temporary error and could not complete your request.”, e.g.:
“The server, while acting as a gateway or proxy, received an invalid response from the upstream2 server it accessed in attempting to fulfill the request.”Unfortunately, the error does not necessarily indicate what was requested, from which “upstream” server, and what the invalid response was.
In the context of Microsoft ISA Servers:
Microsoft Knowledge Base article 938465: “Error message when you try to access Web sites through a downstream server after you enable hotfix 927265 on an upstream server that is running ISA Server 2004 or ISA Server 2006: “502 Proxy Error””asking the website administrator to fix the problem.
You may also find that the problem disappears if you retry later. You could monitor the website to determine when it returns to service.HTTP 504 errors also arise from gateway/proxy problems, but arise when no response is received from a downstream server. 1 Although “Bad Gateway” is usually reported as the reason for HTTP 502 errors, they can also arise from problems with proxies, which are slightly different from gateways in that they do not act like origin servers.
2 Note that “upstream” here is in the context of the response, so the invalid response came from a server that was “downstream” of the proxy when the request was being sent.
Updated 2 Sep 2011
|Copyright (C) 2012 | Site map | Contact us|