That's what I'd expected, thanks. BTW, https://en.wikipedia.org/wiki/List_of_TCP_and_UDP_port_numbers did the same, except of the two references it cited, one is broken and one is not reliable enough. ________________________________________ From: John C Klensin <john-ietf@xxxxxxx> Sent: Monday, February 20, 2017 20:33 To: Mark Andrews; Danny Niu Cc: ietf@xxxxxxxx Subject: Re: Purpose of Port 0. --On Monday, February 20, 2017 10:07 PM +1100 Mark Andrews <marka@xxxxxxx> wrote: > > In message > <SG2PR06MB071061291C3DC252AA62FCB2C15E0@SG2PR06MB0710.apcprd06 > .prod. outlook.com>, Danny Niu writes: >> Questions: >> Is "Berkerly Sockets API" defined seperately from the BSD >> manpages? Or is it just sections of the BSD manpages? What >> happened to "Berkerly Sockets API"? >> >> Proposal: >> Folks at POSIX are a bit unwilling to dis-certify some >> allegedly existing systems, and think it'd be better IETF >> note the purpose of port 0, so that existing app/sys woudn't >> break. >> So is it too soon to start drafting? > > Well UDP source port 0 means don't reply (RFC 768). It's for > uni directional streams. > > As for 0 to select a ephemeral port that is a BSD sockets > convention. That isn't something the IETF should specify. While _assignment_ of a por is an IETF matter and I mostly agree with Mark, recognition of how one is being used is is a little different. It seems to me that this is rather more an IANA registry matter than a standardization one and that, given practices today, it would be reasonable to annotate the registry by adding "used for" or "known to be used for" to "reserved". That should be mostly a housekeeping matter: could one of the relevant ADs speak up and indicate whether they want an I-D, a note (perhaps just this thread), a formal liaison request from POSIX, or something else? john