Re: [idn] impacted systems investigation

[Mark.Andrews@nominum.com]

> Nobody has presented any evidence of DNS caches having trouble with
> UTF-8. Nobody has presented any evidence of DNS servers having trouble
> with UTF-8. The discussion of server upgrades is divorced from reality.

	I agree with you here.  UTF8 does not require a server upgrade
	unless you want the error messages to put out UTF8 rather than
	RFC1035.  Most will even allow entry of UTF8 in master files
	even though it is out of scope.  For those that don't the
	translation from UTF8 to RFC1035 is easy and reversable.

	The wire format has always supported UTF8 as it was designed to
	support 8 bit names.

> 
> There are some widely distributed DNS _client_ libraries that, in
> violation of RFC 2181, reject DNS names containing unusual characters.

	gethostbyname() and gethostbyaddr() are clients of the DNS
	and as such are not covered by RFC 2181.  Clients of the DNS
	are perfectly entitled to reject any answer they get back from
	the DNS.

> In particular, the version 8 libresolv gethostbyname() implementation
> does this; look at gethostans(), maybe_ok(), res_hnok(), and res_dnok().
> Sysadmins can fix it by putting no-check-names into /etc/resolv.conf.
> 
> ---Dan
--
Mark Andrews, Nominum Inc.
1 Seymour St., Dundas Valley, NSW 2117, Australia
PHONE: +61 2 9871 4742                 INTERNET: Mark.Andrews@nominum.com