REMOTE_ADDR Weirdness

Here's a brain teaser for you guys. I'm using the PHP fopen() function with
Linux/Apache to read HTTP data from one web server to another (not all that
unusual as I understand). REMOTE_ADDR is supposed to have the IP address of
the requestor when the responding server script runs, and it usually does,
except when both web servers are virtual hosts on the same physical server,
in which case REMOTE_ADDR is the same as SERVER_ADDR (not good). I've tried
it on three different virtual host systems, all with the same result.
Twilight Zone, anyone?
--
Phil Mattison
Ohmikron Corp.
480-722-9595 ext. 1