Form $_POST getting scrubbed by server?

I have a super simple script here: http://ecres161.servconfig.com/~sherpaproject/post-test.php Here's the problem: * Enter CAT in box 1 * Enter in box 2 (enclose CAT in tag brackets) The form here simply posts to itself, and then dumps the raw $_POST onto the page. You will see that CAT comes through fine. But does not come through. I'm trying to figure out why, as Inmotion support couldn't crack it. This used to work fine on my old server, but I suspect something at the server level is filtering the $_POST and removing what it sees as suspicious strings. Interestingly, if you put in numeric values like 123 and <123> they *both* come through ok. So, I suspect some sort of regex filtering there. But, I need to know what to ask tech support to disable for me, as I need to be able to receive things like