It's probably impossible to get everybody to agree on
terminology, but at least there should be a list
- database: 1) (abstract) a formally structured collection of data;
2) (concrete) a system of computer software/hardware that implements and
manages a database (abstract).
- gTLD: "generic TLD". RFC1591 used the term "generic TLD"
to refer to TLDs like .com, .net, .org, .mil, .gov, and .edu in
opposition to the country code TLDs like .us, .fi, .it, and so on. The
IAHC report particularized the term "generic TLD" to mean "a TLD that
was 1) not a ccTLD, 2) with no registration restrictions on the type of
entity that could register in it". The IAHC report resulted in the
formation of the gTLD-MoU, which got far wider public exposure than
RFC1591 ever did, and consequently most people who come into the debate
are only familiar with the IAHC definition. In particular, the person
who wrote the charter for WG-C was using the IAHC definition, not the
RFC1591 definition. The term "open TLD" has some currency, but it
- gTLD registry: a registry for a particular gTLD ("the .com
- policy authority: an entity that has authority over
policy. Different entities may have authority over different policy
areas, and, since in general both the term "policy" and the term
"authority" are very broad, combining the two gives a result almost
guaranteed to cause confusion and argument. In the context of the gTLD
discussions, a "Policy Authority" generally means an entity that sets
high-level overall policy for a TLD. For open TLDs the default policy
authority could be said to be ICANN.
- Registrar: an entity with a direct contractual relationship with,
and special access to, a registry, that inserts records on behalf of
- Registration agent: Registrar. Nominet makes a distinction here
that I don't fully understand -- if someone can explain that distinction
I would like to know..
- Registry: a database associating DNS information with some person,
legal entity, operational entity, or other referrent. Note that we can
speak of a registry in the abstract or in the concrete, as per the
definition of "database" above. To emphasize the abstract meaning we
may use the terms "registry database", or possibly "registry data".
- Registry Administrator: An entity delegated administrative
authority the registry. CORE was the administrator of the prototype
- Registry Operator: the organization or business that
operates a registry. This distinction is very important: NSI is the
operator of the .com registry; Emergent was the operator of the
prototype CORE registry.
- Shared Registry: a registry that allows access from
multiple distinct registrars.
- Shared Registry System (SRS): the software that supports a
shared registry. There are several extant shared registry systems --
NSI, CORE, and Nominet all have functioning SRSs.
- Sponsor: an entity with policy authority over a TLD.
- SRS: Shared Registry System
- Thick vs Thin registry models: In a shared registry system
there is a division of labor between the registrars and the registry.
When Network Solutions (NSI) developed their particular shared registry
system (SRS) they tried to minimize the functionality in the registry
component and maximize the functionality in the registrar components:
the registry keeps the domain name, the name server information, and a
reference to the registrar that registered the name. The registrar
keeps all other information. NSI called this the "thin registry model".
Many people think this would have been better called the "anorexic
registry model", because NSI eliminated keeping whois information from
the responsibilities of the registry -- a function many people think
must be centralized. Another label might be the "thick registrar
model". The NOMINET model is the reverse, with extremely thin
registrars (the only technical requirement for being a registrar in the
NOMINET model is an email client that can run PGP). The CORE model is
somewhere in between.
- TLD: 1) One of the entries in the IANA-approved root zone.
2) The term may also be used in a generic technical sense to refer to an
entry in any root zone. It is frequent practice to prefix the term
"TLD" with a small letter to indicate some flavor of TLD, as in:
- aTLD: ("alternate" TLD) An entry in some root zone which is
visible on the public Internet when referenced as an IP address, but
which is not included in the IANA root and is therefore not visible
through the public DNS when referenced as a domain name.
- cTLD: ("chartered" TLD) A TLD with a document ("charter")
that defines registration and other policies for the TLD.
- ccTLD: ("country code" TLD) A TLD that has its name derived
from the ISO 3166 list of 2-letter region and country abbreviations.
- gTLD: a TLD that has no enforced criteria for the entities
that may register in it. This departs somewhat from the rfc1591
definition. A gTLD may have a charter; if the charter is enforced it
would be better termed a "chartered TLD".
- pTLD: ("private" TLD) An entry in some root zone other than
the IANA-approved one. Most pTLDs are on private networks; a few are
- whois: "whois" is a simple database system that manages
public information for DNS registrants, and other data associated with
DNS. It uses a simple client-server protocol; whois clients are
available on most unix systems. There have been several attempts over
the years to improve the protocol -- there are RFCs for other versions
of whois, but they have never reached wide acceptance or use.
- whois data: Information kept in the whois database. The
most important information kept in whois for a domain name are 1) the
"registrant" information -- the name and legal address of the
registrant, 2) addresses of the administrative, technical (zone), and
billing contacts, 3) name server information, and 4) update and creation
dates for the record.
- zone: "Zone" is a technical term in DNS with subtleties that are
difficult to explain in a few words. However, for our purposes we may
think of it as the information that defines a part of the DNS hiearchy
that share a common prefix, and that does not contain information for
lower level zones. Zone entries can either be direct information (eg,
the IP address of a host in the zone), or information that dscribes the
hierarchy of zones (the "glue" records that connect zones). For
example, the .com zone contains several million entries, most of which
reference a lower level zone (subzone), ie, mostly glue. aol.com is a
subzone of the .com zone; it contains some 16 million entries, most of
which are direct data.