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Re: RFC 2553 bind semantics harms the way to AF independence



On Wed, 27 Jun 2001, Jun-ichiro itojun Hagino wrote:

>
> >> => you can use it with the V6ONLY stuff.
> >yes, but on rfc2553-compliant system you cannot have both an AF_INET
> >and an AF_INET6 socket listening on the same port.
>
> 	(just a picky comment)  RFC2553 does not talk about the behavior
> 	when try to bind(2) to both :: and 0.0.0.0 on the same port.  some
> 	systems reject bind(2) to 0.0.0.0, some does not.

ok. i will try to explain better my thoughts.

i don't want to change RFC2553. i think that V6ONLY is a very good feature
and may be sufficient to achieve a good af-indipendence. however, this
moves the focus on the behaviour of bind and getaddrinfo (which is not
described in detail in RFC2553 - i suppose because there is no consensus).

some implementations of bind(2) allow binding of 0.0.0.0 and :: address
on the same port, and some do not. i think that this may be a problem for
the developers which are working in multi-platform environments.

i'd really like to minimize the negative effect of this behaviour, but i
understand that there is not much that can be done about this.

i hope that we will come to a *BSD-like de-facto standard for the
behaviour of bind and getaddrinfo, but i wonder if having no standard
is even worse than having a bad standard (linux-like).

-- 
Aequam memento rebus in arduis servare mentem...

Mauro Tortonesi			mauro@ferrara.linux.it
Ferrara Linux User Group	http://www.ferrara.linux.it
Project6 - IPv6 for Linux	http://project6.ferrara.linux.it

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