[dns-operations] about the underline in hostname

[Fred Morris]

On Thursday 29 May 2014 00:24, hua peng wrote:
> I found this is a valid RR:
> 
> _spf.yandex.ru.         2768    IN      TXT     "v=spf1
> include:_spf-ipv4.yandex.ru include:_spf-ipv6.yandex.ru ~all"

The general geist... feng shui... the way it hangs... (how many languages can 
I offend?): ANY OCTET is legal in a label.

HOWEVER, because of concerns regarding hostnames I can't, for instance, 
register "rm -rf *.com". (*cough* Khazakhstan)

BUT if I own m3047.com (and I do!) I *could* (but don't!) serve any RR I so 
desire under that domain. (Regarding all numbers, I own 2535385091.org... 
it's my phone number.) And I reserve the right to serve anything I want under 
m3047.com. For legal purposes. (Which reminds me, but that's another post.)

There is also some confusion about the notion of "domain". A domain, as far as 
the DNS is concerned, is a concatenated list of labels, served from a known 
root. No, no, no I'm wrong. A domain is a ermmm Domain that someone can buy! 
How forgetful of me! What I'm getting at is that when they wrote this stuff 
they were mathematicians, and a  "domain" had to do with where knowledge was 
present (hence NXDOMAIN vs ANSWER:0). So especially when you read old RFCs, 
keep that in mind.

> But for A, CNAME, AAAA etc, the underline in hostname is invalid.
> Does this make a confusion?

That seems like an error on the side of overly restrictive. Are you certain? 
Are you really sure that the DNS is what is obstreperously impeding your 
happy path?

--

Fred Morris