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I have such trouble. There are nginx (as frontent to apache) and apache with mod_rpaf installed. It worked good for a month or so. But today error 502 returned to some requests to php (not all requests cause this error). And it's a great mistery)), 'cause nothing was removed, nothing was installed\upgraded.

Some investigation cleared that:

  • this doesn't depend on heaviness of request - error returned in less then a second (so it's not timeout).

  • removing of mod_rpaf cleares the problem

Are there any ways to workaround this issue or maybe could you guess me some alternative to mod_rpaf.

Thanks in advance!

EDIT -------------------

actually error was caused with big size of firephp headers, so in some way it caused mod_rpaf to fail. resolved by reducing headers size and disabling mod_rpaf (thanks to @coredump) now I have client IP adress in $_SERVER[X-Forwarded..]

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Why you use mod_rpaf and can you simulate the error using curl and injecting the X-Forwarded-For header from the command line? Also, is there any error on the log about what exactly happened when the 502 error appear? Maybe increasing the apache's LogLevel will help on that. –  coredump Apr 19 '11 at 11:36
@coredump yeah, thanks I've guessed a couple minutes ago to check $_SERVER array and found that X-Forwarded... was there. So already mod_rpaf is not really needed)) –  kradmiy Apr 19 '11 at 12:33

1 Answer 1

If your headers are too large, that might cause a problem.

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