Hacker News Reader

Comment by the_mitsuhiko | Hacker News Reader

I'm to blame for 5000 being popular as HTTP port as I picked it by default for Flask. The reason I did this was that there is only one HTTP port (other than 80 you can't bind to) in the IANA registration which is 8080. A few people started using other ports around the time because 8080 was commonly already occupied by some userspace HTTPDs.

I picked specifically 5000 because the IANA registration for this port was assigned to a single service, was not used and generally obscure. Whatever Apple has running on there is also unlikely to be what the IANA registration refers to.

View on HN

> 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.

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.

Does Multiplex Communication sounds familliar? But yeah, someone should check the IANA archives to know what really is "commplex-main".

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...

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.

Reply on news.ycombinator.com