remote_addr global change

hi - apparently my internal ip issues can be resolved by changing:

$_SERVER['REMOTE_ADDR'];

And replace it with this snippet of code,
$_SERVER['HTTP_X_CLUSTER_CLIENT_IP'];

Is there a way to change this globally? I did a basic search on /modules and the uploaded modules and found a few (trackback, comment, etc) but is there a way to do this without changing the code in each one?

Thanks!