i have domain masking turned on through domain registrar displays foo.org in address bar. discovered after customers sign via paypal, , returned site along post data site process, variables automatically appended url this: foo.org/success.php?txn_id=kb0099898yp&txn_status=sdlkfjbsdkljfbsdkjb&etc . trouble is, these variables remain in address bar indefinitely, if click on link , page loads! if refresh page, no matter go on site after this, resubmits data server processing! this happens if customer manually appends url. never goes away. i have looked on , google, , i'm either not asking right question, or no 1 else has had problem before :) how remedy this?