[Pdns-dev] Re: [Pdns-users] Re: Domains with binary (e.g. UTF-8) labels

bert hubert bert.hubert at netherlabs.nl
Sun Dec 17 13:32:03 CET 2006

On Sun, Dec 17, 2006 at 12:48:08AM +0000, Julian Mehnle wrote:

> > It also requires some work on the database side of things, as for
> > example PostgreSQL is fond of interpreting 'VARCHARs' as UTF-8, which a
> > random label very often is not.
> I'm not sure I understand what you're saying here.

You want UTF-8. But it is stated nowhere that DNS should be UTF-8, there is
only an RFC that says DNS is '8 bit clear', although in practice it
isn't, which explains my relative lack of interest.

If the database thinks in UTF-8, but something comes along that isn't (hint,
many random 8-bit octet-strings are not valid UTF-8!), it refuses the data.

So the database needs to stop thinking and accept, and match, binary labels,
while remaining case insensitive!

Stephane hinted at that already. I don't see how this should work. If we
accept binary labels, we might match these when you don't expect them to.

For example, a binary label containing the letter 'b' will also be matched
by that same label containing the letter 'B', which might mean something
differently to you.

For UTF-8 content, it doesn't matter, but for other binary uses it might.

DNS does not accept 'abcde' and 'abcDe' as "brothers" in a zone, but from a
binary standpoint they are different.

I'm not going to work out these complications, this will be up to the people
that want 8-bit labels in PowerDNS. If I see a solution, I'll implement it,
but right now things look rather useless.


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