>The difference in blocking any of the existing ports on your list and >blocking UDP/1900 is that the ports on your list are all registered >ports. Port 1900 is not registered -
IANA is under the impression it's registered for SSDP. Do you have some reason to believe they're mistaken? http://www.iana.org/assignments/service-names-port-numbers/service-names-port-numbers.xhtml?&page=34
