> Whatever Apple has running on there is also unlikely to be what the IANA registration refers to.

Here's a quotation:

> Just did a bit more digging, and IANA actually assigns port 5000 to "commplex-main" - so really any other service that's using that port is violating the official assignment. Based on a quick search of what commplex-main is, it's related to UPnP for network device discoverability. I'm not sure exactly what the AirPlay Receiver service does, but I get the gist that it probably does fit somewhere into the scope of UPnP-related features. At the very least, it's probably a far more accurate usage of port 5000 than some random dev servers.

This port was actually also used back in XP and * Lion days both by Apple and Microsoft, but I have a hunch that *.local replaced these use cases and that's why it became disused until recently.