Subject: Re: release and A instead of AAAA?

Re: release and A instead of AAAA?

From: Erik Kline <ek_at_google.com>
Date: Wed, 8 Dec 2010 15:24:16 -0800

On 8 December 2010 14:51, Steinar H. Gunderson <sesse_at_google.com> wrote:
> Den 8. desember 2010 20:10 skrev William Ahern
> <william_at_25thandclement.com> følgende:
>> Some will route an IPv4-mapped address through the IPv4 network.
>
> This would be correct behavior.
>
>> Others will route it through the IPv6 network regardless.
>
> This would be broken behavior. (Mapped addresses are explicitly not
> meant to be sent on the wire.)
>
>> Still others will just
>> drop them entirely because of security concerns--on OpenBSD IPv4-mapped
>> addresses are rejected immediately inside both bind(2) and connect(2).
>
> This would be “OpenBSD just wants to be difficult”. :-)
>
>> So an interface isn't really being helpful in crafting mapped addresses
>> because the application still has to deal with all of the policy regardless.
>
> You can turn it around; c-ares shouldn't be ignoring to do The Right
> Thing(TM) just because there are broken operating systems out there.

Agreed. AIUI, the behaviour as it stands is essentially de facto
standard operating procedure. If you want different behaviour you can
obviously write your own wrapper method.
Received on 2010-12-09