I get the reasoning why there is only a single port for http connections, but why was the number chosen to be 80? Why not 76, or 111 or 2? What is the reason behind the number 80? (Or why 443 for https? Or 21 for ftp?)

  • Unfortunately, questions that are "historical trivia that does not allow for a concise and non-subjective answer or is trivial/irrelevant to modern networking" are explicitly off-topic here.
    – Ron Maupin
    Jan 20 '19 at 1:25

Tim Berners Lee (aka TBL) choose port 80 in the early 1990s; at one time, TCP port 2784 was used, but TBL deprecated it in favor of using port 80.

TBL came up with ENQUIRE, which was the building block for hypertext in 1980, but it took almost a decade for the protocol to mature. One might speculate that 80 is a reference to 1980, but that's pure speculation AFAICT.

There is no real reason we have to choose port 80, other than the need to have a well-known port, and that IANA standardized on port 80 so long ago.

  • Also view the explanation here, which suggests that 80 was used since it was free and 79 and 81 were not (couldn't find the primary source though)
    – Jedi
    Jun 4 '16 at 4:57

Not the answer you're looking for? Browse other questions tagged or ask your own question.