ffproxy doesn't support http headers which size is > 2048 bytes, causing some web sites to return http 400 errors (bad request) to your browser.
But it's easy to fix.
You have to update 2 lines of code in request.c:
line 188 : char buf; ==> char buf;
line 293 : char buf; ==> char buf;
and recompile with "make"
Please note this is a quick & dirty fix, but it's doing the trick !!
The line to insert is:
sa_len = sizeof sa;