Okay - every single one of those Microsoft Windows rejects specifies Port
1900, which IANA lists as

"ssdp 1900/udp SSDP"

SSDP = "Simple Service Discovery Protocol" - has to do with
networking/multicasting (which is installed by default in XP.) The protocol
is at http://www.upnp.org/download/draft_cai_ssdp_v1_03.txt

That states - among much else that I am not engineer enough to interpret -

" Discovery occurs when a SSDP client multicasts a HTTP UDP discovery
request to the SSDP multicast channel/Port. SSDP services listen to
the SSDP multicast channel/Port in order to hear such discovery
requests. If a SSDP service hears a HTTP UDP discovery request that
matches the service it offers then it will respond using a unicast
HTTP UDP response. "

What do you think? Bug in the OS?