[dns-operations] about the underline in hostname

Fred Morris m3047 at m3047.net
Fri May 30 03:35:42 UTC 2014

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

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