In message <SG2PR06MB071061291C3DC252AA62FCB2C15E0@xxxxxxxxxxxxxxxxxxxxxxxxxxx. 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. Mark > ________________________________________ > From: joel jaeggli <joelja@xxxxxxxxx> > Sent: Monday, February 20, 2017 16:53 > To: Danny Niu; ietf@xxxxxxxx > Subject: Re: Purpose of Port 0. > > On 2/20/17 12:30 AM, Danny Niu wrote: > > Hi, all. > > > > Recently on the POSIX mailing list, there's a discussion on the > > correct way to bind to (or listen on) an ephemeral port. While I > > referenced the "UNIX Network Programming", we're not quite satisfied > > because even though it's co-written by someone involved in IETF, it's > > still JUST a textbook. > > > > The canonical way to do this, according to some (from > > stackoverflow.com, and other places), is to bind to port 0, which I > > assume had been reserved for this purpose, but I haven't find > > anything to back this up yet. > > > > On the POSIX list, they suggested that IETF should, (or should have > > already) state(d) that port 0 be reserved for binding to ephemeral > > ports. So can we find any reference for this? Or should we draft an > > RFC? > > The original convention is from berkeley sockets api, so it's been that > way since 1983 or so. it would predate therefore ieee 1003 by some > years. I would. suspect that Postel et al were well aware that it was > employed by that convention when it was noted as reserved in rfc 1340/1700. > > > Thanks. > > -- Mark Andrews, ISC 1 Seymour St., Dundas Valley, NSW 2117, Australia PHONE: +61 2 9871 4742 INTERNET: marka@xxxxxxx