In <20041228103936(_dot_)GA26942(_at_)alatheia(_dot_)elm(_dot_)net> Alex van
den Bogaerdt <alex(_at_)ergens(_dot_)op(_dot_)het(_dot_)net> writes:
On Mon, Dec 27, 2004 at 08:08:32PM -0800, william(at)elan.net wrote:
> You talk about DNS domains as a group of records. I think this is
> not correct.
> In "inmail-backup1.elan.net", this entire name is a DNS domain,
> so are "inmail-backup2.elan.net" and "inmail-backup3.elan.net".
> The way you describe it, the domain would be "elan.net".
> DNS ZONE has a similar problem.
DNS domains are in fact groups of HOST records and DOMAIN is something
that has been delegated within DNS hierarchy (i.e. its what is pointed
Again: I think you are confusing zones, domains and other related
stuff. If you are going to present it as a fact sheet, make sure
you get it right.
I'm just now catching up on a large backlog of unread SPF-discuss
I have to agree with Alex here. Your definitions of Host, FQDN,
Domain, zone, etc. are very different from my understanding of the
terms. My understanding seems to be much closer to Alex's.
You are describing a ZONE and are calling it a domain. That in
itself is not wrong, because a zone _is_ a domain. However, it
is not true that a domain must be a group of hosts.
inmail-backup1.elan.net is ALSO a domain.
Zones are where delegation occurs. This is part of the DNS-tree
that is delegated to another authority, it has a SOA record.
Starting somewhere inside the DNS-tree, follow the entire path
upto the root and concatenate every LABEL you find (separated
by dots) to get a domain.
A hostname is just one kind of domain.
A hostname is always a domain; domain is not always a hostname
I will add another thing:
Host: A computer attached to the internet. A host may have one or
more names. A host may also have one or more interfaces (IP address),
although hosts with more than one interface is also often called a
foo.bar.com IN TXT "you are here"
mail.bar.com IN A 192.0.2.1
mail.bar.com IN A 126.96.36.199
www.bar.com IN A 188.8.131.52
"foo.bar.com" is a domain name, but not a hostname since it just has a
TXT record. There can't be a computer called foo.bar.com.
"mail.bar.com" is both a domain name and a host name. It has two
"www.bar.com" is the same host as mail.bar.com, but specifies only one
interface to be used to reach it.