yeah, I did a quick search on REMOTE_ADDR before I saw your reply, and found it in the following scripts.
libs/captcha.inc.php:
libs/includepoll.inc.php:
libs/ubbthreads.inc.php:
libs/mysql.inc.php:
libs/phpmailer/class.phpmailer.php:
scripts/captcha.inc.php:
scripts/addpost.inc.php:
scripts/adduser.inc.php:
scripts/dopoll.inc.php:
scripts/shoutit.inc.php:
scripts/start_page.inc.php:
Which is a fair amount to go poking around in.
Most of them are of the form
$ip = find_environmental('REMOTE_ADDR');
so changing them to
$ip = find_environmental('X_FORWARDED_FOR');
should work without too much anguish.
The captcha seems to use it as part of generating unique image names. Of course, making this change will mean that the forums wouldn't work if they *weren't* behind a proxy that sent the X_FORWARDED_FOR header, but that's a different issue.
Oh, and we are currently running UBBThreads 7.1, and plan on upgrading in the not to distant future to the latest version.
