AAAA, A6, or both?

[Antonio Querubin]

On Fri, 18 Jan 2002, John Klos wrote:

> > | Could anyone please advise me as to which approach I should take?
> > | Every time I read up on this I only get more confused.
>
> > You should use AAAA and disregard anything you ever read about A6.
>
> AAAA is depricated but still supported. If you fear that you might have
> systems that can't do RFC 2874 type A6 chains, BIND 9 has an option that
> allows RFC 1886 lookups to be done on A6 chains.
>
> I'd love to know what, if any, resolvers can do 1886 lookups but not 2874.
> Does anyone know?
>
> I am interested to know why you dismiss A6 out of hand with no
> information. Have you come across RFC 1886-only resolvers?

Very few service providers have upgraded their production DNS to handle A6
so I suspect the vast majority of DNS currently in operation will still
barf on A6 RRs.  If I recall correctly, BIND 8.x and earlier, for example,
will reject an entire zone if it sees RRs it doesn't understand, so it's
not likely you'll see A6 become widespread until BIND 9.x is more widely
deployed on DNS operating as secondary nameservers.