Re: DNS and subdomains

[William Herrin <bill () herrin us>]

On Fri, Feb 28, 2025 at 12:50 PM David Conrad <drc () virtualized org> wrote:
> On Feb 28, 2025, at 12:18 PM, William Herrin <bill () herrin us> wrote:
> > Remember my example cat.p.dirtside.com? P.dirtside.com is a subdomain
> > of dirtside.com. It's an administrative grouping of domain names that
> > have a particular characteristic. However, p.dirtside.com is NOT a
> > domain name. It has no DNS records of its own. Only subsidiaries like
> > cat.p.dirtside.com exist and have DNS records.
>
> Hmm.
>
> I would definitely have said “p.dirtside.com" is a subdomain.

Hi Dave,

I agree that "p.dirtside.com" is a subdomain. Recheck what I said.
It's not a domain name, no more so than "sdkflkdfgfsgdfg". That's the
contradiction.

It gets worse. Is "cat.p.dirtside.com" a subdomain? It's definitely a
domain name. You can know it's a subdomain if you find another domain
name like abc.cat.p.dirtside.com. But if you don't find another name,
how can you as an external observer know that cat.p.dirtside.com is
NOT a subdomain?

Regards,
Bill Herrin



-- 
William Herrin
bill () herrin us
https://bill.herrin.us/