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> 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

> 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.

the_mitsuhiko 5y ago
I believe that comment to be incorrect. UPnP is using this port, but unofficially. The IANA port registration for 5000 is for commplex whatever it is, and it refers to two ports: 5000 and 5001. UPnP uses 5000 unofficially and does not use 5001.
- zinekeller 5y ago
  Does Multiplex Communication sounds familliar? But yeah, someone should check the IANA archives to know what really is "commplex-main".
  - the_mitsuhiko 5y ago
    It would appear commplex was a part of seeplex, some visualization tool for old Sun workstations in the early 90ies: https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=11617&context=rtd https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=11617...
    - zinekeller 5y ago
      It's actually called "Triplex", Commplex and Seeplex are part of Triplex. > The Commplex is a communications package for communication with the NCUBE from Sun workstations. Wait, all roads lead to Oracle? So, uhm, this reminds me of STMPS and port 465. Read about it, and it's a sad state of affairs because of a blunder in managing that list. Funnily, mail providers and Cisco share that port (and no, not a TCP/UDP split, both are for TCP connections). So who suggested to use port 5000 then way back? That's a serious question that is now my homework for this conversation.

the_mitsuhiko 5y ago

I believe that comment to be incorrect. UPnP is using this port, but unofficially. The IANA port registration for 5000 is for commplex whatever it is, and it refers to two ports: 5000 and 5001. UPnP uses 5000 unofficially and does not use 5001.

zinekeller 5y ago
Does Multiplex Communication sounds familliar? But yeah, someone should check the IANA archives to know what really is "commplex-main".
- the_mitsuhiko 5y ago
  It would appear commplex was a part of seeplex, some visualization tool for old Sun workstations in the early 90ies: https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=11617&context=rtd https://lib.dr.iastate.edu/cgi/viewcontent.cgi?article=11617...
  - zinekeller 5y ago
    It's actually called "Triplex", Commplex and Seeplex are part of Triplex. > The Commplex is a communications package for communication with the NCUBE from Sun workstations. Wait, all roads lead to Oracle? So, uhm, this reminds me of STMPS and port 465. Read about it, and it's a sad state of affairs because of a blunder in managing that list. Funnily, mail providers and Cisco share that port (and no, not a TCP/UDP split, both are for TCP connections). So who suggested to use port 5000 then way back? That's a serious question that is now my homework for this conversation.