[imp] Attachment problem using mod_proxy

[Jean-Michel Besnard]

Hi,

I am using mod_proxy to set a frontend server that reverse every http request to IMP, installed on a backend server.

I have problems using the composer when attaching big files (let's say 6Mb).
The problem comes that way :
 -I browse my directory to find a file to attach
 -I attach it (The file is uploaded without any problem)
 -I send the message and then I get :



Proxy Error The proxy server received an invalid response from an upstream server.

 The proxy server could not handle the request POST /horde/imp/compose.php.

 Reason: Document contains no data

The message comes from the front end. I dont have any error in the error log file.

I have tried to set directives in apache to increase the buffer max size:
LimitRequestBody 2147483647/
ProxyReceiveBufferSize  51200000
ProxyIOBufferSize 51200000

These values should be more than enough but I still get the same error.

Any clue ?

Thanks,

Jean-Michel