I am working on a small application on an embedded platform which has to send some classified information to a server. This connection to the server is encrypted using SSL. The encryption is tunneled trough a proxy - in this case a Zentyal proxy. The embedded application is written in C and the connectivity part is done with wolfssl and lwip.
The application works fine with Zentyal 5.1. But recently the proxy server was updated to 6.1 and now the connection is falling all the time. Debugging the issue, I have found the problem occurs when the application ask the server for a tunnel connection. What I see happening is that the application sends the CONNECT request to the proxy ...
... to which the the proxy answers with a 200 Connection Established.
But after that packet is received the proxy send another message with Proxy-Coneection:Close. Whith has the effect that the connection is shut down before the SSL handshake.
I have tried different configuration in the Zentyal (transparent proxy enable, disable cache, etc.) but the error remains the same. Also, I have added different HTTP headers like proxy-connection: Keep alive. But the connection is still being closed.
Maybe this is a problem with the 6.1 version. I have tried looking through the change log but there is no reference to any change in the processing of the connect request. Neither are there any known problems related to the way the connect is being handled.
Any advice?
