In message
<SG2PR06MB071061291C3DC252AA62FCB2C15E0(_at_)SG2PR06MB0710(_dot_)apcprd06(_dot_)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.
Mark
________________________________________
From: joel jaeggli <joelja(_at_)bogus(_dot_)com>
Sent: Monday, February 20, 2017 16:53
To: Danny Niu; ietf(_at_)ietf(_dot_)org
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(_at_)isc(_dot_)org