Finjan Software SurfinGate 6.0 and 6.0 1 allows remote attackers to bypass URL access restrictions via a URL whose hostname portion uses a fully qualified domain name (FQDN) that ends in a "." (dot).
http://www.securityfocus.com/bid/5634
http://www.iss.net/security_center/static/10037.php
http://archives.neohapsis.com/archives/bugtraq/2002-09/0043.html