How can I tell a host name from a subdomain

[Herb Martin]

> > Somebody gave me her web site address.
> >
> > It's like vi.somename.com .
> > (somename is an example and vi and com are real).
> >
> > vi.somename.com could be a host name and a subdomain.
> > Is there a way to tell one from the other without asking her?
>
> Technically every DNS name (except the root name) is a "subdomain" of
> some other DNS name. It's a purely relative term, like "subdirectory",
> "subcategory" and so forth.

Yes, and it's even worse than that (technically.)

Technically every DNS host full name is a "domain name" too.
Although it is relatively uncommon to hear anyone claim
a full machine name is a domain name, this qualifies.

They are all names in a domain (area of control or authority.)

He also cannot tell because some "domain names" are also
the names of specific hosts.

> Why do you care about the difference between a host name and a
> subdomain? You access it via a browser the same way regardless.

Right.

Ultimately, if he can use some service there "it's a host name"
(in the sense he means the question.)

But if there are other names below it then -- in the sense he
means it -- it's a domain name too.  <grin>