[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

Re: v6ops-v6onbydefault: link-locals and AI_ADDRCONFIG



> [...]
> > - IMHO, getaddrinfo()'s job should be to report what is in DNS, not
> > to try to
> >   coerce apps into behaving well.  So even though apps shouldn't be
> >   using link-local addresses, and even though people shouldn't list
> >   link-local addresses in DNS, getaddrinfo() should not try to hide
> >   such addresses from apps if they happen to appear in DNS.
> 
> I can sympathize with your opinions. I think two things are needed:
> 
> o A standard call that most applications can use in a simple way. IMHO
>   it should query DNS, other name services, /etc/hosts etc.
> 
> o A standard call that applications can use to check what is in DNS
> 
> The first should IMHO be something like getaddrinfo() where
> applications simply try the addresses in the order they are returned. 

I don't think that we should be defining getaddrinfo() in terms of
"whatever lookup service happens to be around" because it's very
difficult to get reliable and repeatable behavior that way.  

> I also think it
> should be possible for an administrator to define which name services
> should be used, which type of addresses should be returned, and the
> order.

I disagree.  Different apps have different needs, and no single
host-wide or site-wide policy can accomodate the needs of the variety of
apps in use. Also, apps often cross administrative boundaries, which
creates problems when different nodes of those apps are subjected to the
whims of different administrators.

> Another matter is what the API should be. Most IPv6 enabled
> applications today use getaddrinfo(), while specialized DNS
> applications like "host" use their own resolver routines.

It's not just specalized DNS applications that need to know what really
is in DNS.  Many apps need consistent views of DNS without having to
second-guess the local host API implementation, brain-damaged sysadmins,
etc.

Keith

--------------------------------------------------------------------
IETF IPv6 working group mailing list
ipv6@ietf.org
Administrative Requests: https://www1.ietf.org/mailman/listinfo/ipv6
--------------------------------------------------------------------