Apache, IIS and 502 proxy error

Saturday, February 7, 2009

I have some servers in my network. There is one public Apache server that proxies requests to these servers. These servers are not directly visible from internet. Some of these servers run IIS and ASP.NET web applications. When accessing these servers through internet then sometimes Apache reports a problem: 502 proxy error.

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13 Comments

This post is very timely. I just set up dev environments for me and my co-workers at my job, and this issue has been frustrating us. Many thanks.

Micah Nolte - Wednesday, February 11, 2009 6:15:30 PM

You are welcome :)

DigiMortal - Wednesday, February 11, 2009 6:47:25 PM

Nice blog
I am facing same problem. I have done the above mentioned changes SetEnv. But still getting the same error.I am using apache 2.2.3

kiran - Tuesday, August 11, 2009 10:33:01 AM

This solution worked for me, thanks for posting it

Justin - Wednesday, August 26, 2009 11:17:17 AM

Good Solution.. Worked for me..

Henry - Thursday, September 3, 2009 11:03:39 AM

Firstly, I would like to know the impact of 502 error. When the apache act as proxy reported 502, how the apache will assume the status of IIS servers?

On other hand, the two setenv will fallback to httpd/1.0 without keepalive. Does it may increaes the TCP sockets needed to be opened as no more keepalive?

This will increase the loading for the IIS server.

Ivan Tsui - Monday, September 21, 2009 9:19:39 AM

I am getting this error in two scenarious after this env setting is done,
if the request that is made from the browser is time taking/bigger size data as a result.
and observed if number of simultaneous requests are in the range of 5-10

Please help me

kiran - Friday, May 14, 2010 7:27:59 AM

Althu, this was written in 2009, but helped me last day. Was having same issue and was unable to find root couse. This helps. Thanks a lot and keep up the good things.

Fasih Hansmukh - Tuesday, May 10, 2011 11:40:44 AM

Great! This is exactly what I was looking for and it works! Thanks!

Eric - Friday, June 17, 2011 7:57:25 PM

I had a similar problem and resorted to turning of HTTP keep-alive among the common response headers in IIS. Works for both IIS6 and IIS7.

Ted - Monday, October 10, 2011 11:06:46 AM

Checked out your Gateway IP, Same problem did hurt me also on inspection i found that i did't give my Gateway IP to my LAN Card.

Bilal - Tuesday, November 22, 2011 4:42:35 AM

After upgrading my IIS backend from Windows 2003/IIS6 to Windows 2008/IIS7 I suddenly got 502 errors. Thanks to this post I was able to sort out the issue, thanks a lot!!!

Martijn Balink - Thursday, December 8, 2011 10:03:57 AM

Thanks DigiMortal, this solved a very big problem for me!

/ Jakob

Jakob Simon-Gaarde - Wednesday, September 5, 2012 6:09:08 AM

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