This is a simple combination of a small C module for apache and another one in Perl for mod_perl

In lots of cases , you end up with a lightweight docserver in front of a heavyweight mod_perl enabled
server.  This is a good thing for speed and performance (see http://perl.apache.org/guide).

The problem this combination tries to solve is that the mod_perl server doesn't know anything about
the client connection, since it's only talking to a doc server.

Install the C module in the doc server like so

cd apache-src
./configure --with-plenty-of-options -add-module=/path/to/mod_proxy_add_info.c

And you just need to put the Perl module in the mod_perl server
perl Makefile.PL
make && make test && make install

And in httpd.conf
PerlModule Apache::Proxy::Info
PerlTransHandler Apache::Proxy::Info;

Currently 3 pieces of information are passed thru

$r->connection->remote_ip()
$ENV{'HTTPS'}
$r->header_in('Host');


Enjoy!