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Network Working Group A. Cooper
Request for Comments: 1480 J. Postel
Obsoletes: 1386 June 1993
The US Domain
Status of this Memo
This memo provides information for the Internet community. It does
not specify an Internet standard. Distribution of this memo is
unlimited.
Table of Contents
1. Introduction ................................................ 2
1.1 The Internet Domain Name System......................... 2
1.2 Top-Level Domains....................................... 3
1.3 The US Domain .......................................... 4
2. Naming Structure ............................................ 4
2.1 State Codes ............................................ 8
2.2 Locality Names.......................................... 8
2.3 Schools ................................................ 10
2.4 State Agencies.......................................... 15
2.5 Federal Agencies ....................................... 15
2.6 Distributed National Institutes......................... 15
2.7 General Independent Entities............................ 16
2.8 Examples of Names....................................... 17
3. Registration ................................................ 20
3.1 Requirements ........................................... 20
3.2 Direct Entries ......................................... 21
3.2.1 IP-Hosts............................................. 21
3.2.2 Non-IP Hosts ........................................ 21
3.3 Delegated Subdomains ................................... 24
3.3.1 Delegation Requirement............................... 26
3.3.2 Delegation Procedures ............................... 28
3.3.3 Subdomain Contacts................................... 29
4. Database Information......................................... 30
4.1 Name Servers ........................................... 30
4.2 Zone files ............................................. 30
4.3 Resource Records ....................................... 31
4.3.1 "A" Records ......................................... 32
4.3.2 CNAME Records ....................................... 32
4.3.3 MX Records .......................................... 33
4.3.4 HINFO Records ....................................... 33
4.3.5 PTR Records ......................................... 33
4.4 Wildcards .............................................. 34
5. References .................................................. 35
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RFC 1480 The US Domain June 1993
6. Security Considerations ..................................... 35
7. Authors' Addresses .......................................... 36
Appendix-I: US Domain Names BNF................................. 37
Appendix-II: US Domain Questionnaire ............................ 42
1. INTRODUCTION
1.1 The Internet Domain Name System
The Domain Name System (DNS) provides for the translation between
hostnames and addresses. Within the Internet, this means translating
from a name such as "venera.isi.edu", to an IP address such as
"128.9.0.32". The DNS is a set of protocols and databases. The
protocols define the syntax and semantics for a query language to ask
questions about information located by DNS-style names. The
databases are distributed and replicated. There is no dependence on
a single central server, and each part of the database is provided in
at least two servers.
The assignment of the 32-bit IP addresses is a separate activity. IP
addresses are delegated by the central Internet Registry to regional
authorities (such as the RIPE NCC for Europe) and the network
providers.
To have a network number assigned please contact your network service
provider or regional registration authority. To determine who this
is (or as a last resort), you can contact the central Internet
Registry at Hostmaster@INTERNIC.NET.
In addition to translating names to addresses for hosts that are on
the Internet, the DNS provides for registering DNS-style names for
other hosts reachable (via electronic mail) through gateways or mail
relays. The records for such name registrations point to an Internet
host (one with an IP address) that acts as a mail forwarder for the
registered host. For example, the host "bah.rochester.ny.us" is
registered in the DNS with a pointer to the mail relay
"relay1.uu.net". This type of pointer is called an MX record.
This gives electronic mail users a uniform mail addressing syntax and
avoids making users aware of the underlying network boundaries.
The reason for the development of the domain system was growth in the
Internet. The hostname to address mappings were maintained by the
InterNIC in a single file, called HOSTS.TXT, which was FTP'd by all
the hosts on the Internet. The network population was changing in
character. The time-share hosts that made up the original ARPANET
were being replaced with local networks of workstations. Local
organizations were administering their own names and addresses, but
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RFC 1480 The US Domain June 1993
had to wait for the NIC to make changes in HOSTS.TXT to make the
changes visible to the Internet at large. Organizations also wanted
some local structure on the name space. The applications on the
Internet were getting more sophisticated and creating a need for
general purpose name service. The idea of a hierarchical name space,
with the hierarchy roughly corresponding to organizational structure,
and names using "." as the character to mark the boundary between
hierarchy levels was developed. A design using a distributed
database and generalized resources was implemented.
The DNS provides standard formats for resource data, standard methods
for querying the database, and standard methods for name servers to
refresh local data from other name servers.
1.2 Top-Level Domains
The top-level domains in the DNS are EDU, COM, GOV, MIL, ORG, INT,
and NET, and all the 2-letter country codes from the list of
countries in ISO-3166. The establishment of new top-level domains is
managed by the Internet Assigned Numbers Authority (IANA). The IANA
may be contacted at IANA@ISI.EDU.
Even though the original intention was that any educational
institution anywhere in the world could be registered under the EDU
domain, in practice, it has turned out with few exceptions, only
those in the United States have registered under EDU, similarly with
COM (for commercial). In other countries, everything is registered
under the 2-letter country code, often with some subdivision. For
example, in Korea (KR) the second level names are AC for academic
community, CO for commercial, GO for government, and RE for research.
However, each country may go its own way about organizing its domain,
and many have.
There are no current plans of putting all of the organizational
domains EDU, GOV, COM, etc., under US. These name tokens are not
used in the US Domain to avoid confusion.
Currently, only four year colleges and universities are being
registered in the EDU domain. All other schools are being registered
in the US Domain.
There are also concerns about the size of the other top-level domains
(especially COM) and ideas are being considered for restructuring.
Other names sometimes appear as top-level domain names. Some people
have made up names in the DNS-style without coordinating or
registering with the DNS management. Some names that typically
appear are BITNET, UUCP, and two-letter codes for continents, such as
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RFC 1480 The US Domain June 1993
"NA" for North America (this conflicts with the official Internet
code for Namibia).
For example, the DNS-style name "KA7EEJ.CO.USA.NA" is used in the
amateur radio network. These addresses are never supposed to show up
on the Internet but they do occasionally. The amateur radio network
people created their own naming scheme, and it interferes sometimes
with Internet addresses.
1.3 The US Domain
The US Domain is an official top-level domain in the DNS of the
Internet community. The domain administrators are Jon Postel and Ann
Westine Cooper at the Information Sciences Institute of the
University of Southern California (USC-ISI).
US is the ISO-3166 2-letter country code for the United States and
thus the US Domain is established as a top-level domain and
registered with the InterNIC the same way other country domains are.
Because organizations in the United States have registered primarily
in the EDU and COM domains, little use was initially made of the US
domain. In the past, the computers registered in the US Domain were
primarily owned by small companies or individuals with computers at
home. However, the US Domain has grown and currently registers hosts
in federal government agencies, state government agencies, K12
schools, community colleges, technical/vocational schools, private
schools, libraries, city and county government agencies, to name a
few.
Initially, the administration of the US Domain was managed solely by
the Domain Registrar. However, due to the increase in registrations,
administration of subdomains is being delegated to others.
Any computer in the United States may be registered in the US Domain.
2. NAMING STRUCTURE
The US Domain hierarchy is based on political geography. The basic
name space under US is the state name space, then the "locality" name
space, (like a city, or county) then organization or computer name
and so on.
For example:
BERKELEY.CA.US
PORTLAND.WA.US
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RFC 1480 The US Domain June 1993
There is of course no problem with running out of names.
The things that are named are individual computers.
If you register now in one city and then move, the database can be
updated with a new name in your new city, and a pointer can be set up
from your old name to your new name. This type of pointer is called
a CNAME record.
The use of unregistered names is not effective and causes problems
for other users. Inventing your own name and using it without
registering is not a good idea.
In addition to strictly geographically names, some special names are
used, such as FED, STATE, AGENCY, DISTRICT, K12, LIB, CC, CITY, and
COUNTY. Several new name spaces have been created, DNI, GEN, and
TEC, and a minor change under the "locality" name space was made to
the existing CITY and COUNTY subdomains by abbreviating them to CI
and CO. A detailed description follows.
Below US, Parallel to States:
-----------------------------
"FED" - This branch may be used for agencies of the federal
government. For example: <org-name>.<city>.FED.US
"DNI" - DISTRIBUTED NATIONAL INSTITUTES - The "DNI" branch was
created directly under the top-level US. This branch is to be used
for distributed national institutes; organizations that span state,
regional, and other organizational boundaries; that are national in
scope, and have distributed facilities. For example:
<org-name>.DNI.US.
Name Space Within States:
------------------------
"locality" - cities, counties, parishes, and townships. Subdomains
under the "locality" would be like CI.<city>.<state>.US,
CO.<county>.<state>.US, or businesses. For example:
Petville.Marvista.CA.US.
"CI" - This branch is used for city government agencies and is a
subdomain under the "locality" name (like Los Angeles). For example:
Fire-Dept.CI.Los-Angeles.CA.US.
"CO" - This branch is used for county government agencies and is a
subdomain under the "locality" name (like Los Angeles). For example:
Fire-Dept.CO.San-Diego.CA.US.
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RFC 1480 The US Domain June 1993
"K12" - This branch may be used for public school districts. A
special name "PVT" can be used in the place of a school district name
for private schools. For example: <school-name>.K12.<state>.US and
<school-name>.PVT.K12.<state>.US.
"CC" - COMMUNITY COLLEGES - This branch was established for all state
wide community colleges. For example: <school-name>.CC.<state>.US.
"TEC" - TECHNICAL AND VOCATIONAL SCHOOLS - The branch "TEC" was
established for technical and vocational schools and colleges. For
example: <school-name>.TEC.<state>.US.
"LIB" - LIBRARIES (STATE, REGIONAL, CITY, COUNTY) - This branch may
be used for libraries only. For example: <lib-name>.LIB.<state>.US.
"STATE" - This branch may be used for state government agencies. For
example: <org-name>.STATE.<state>.US.
"GEN" - GENERAL INDEPENDENT ENTITY - This branch is for the things
that don't fit easily into any other structure listed -- things that
might fit in to something like ORG at the top-level. It is best not
to use the same keywords (ORG, EDU, COM, etc.) that are used at the
top-level to avoid confusion. GEN would be used for such things as,
state-wide organizations, clubs, or domain parks. For example:
<org-name>.GEN.<state-code>.US.
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
VIEW OF SECOND LEVEL DOMAINS UNDER US
+-------+
| US |
+-------+
|
+----------------------------------+
| | | | |
+-----+ +-----+ +-----+ +-----+ +-----+
| FED | | DNI | | TX | | SD | | CA |
+-----+ +-----+ +-----+ +-----+ +-----+
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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RFC 1480 The US Domain June 1993
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
SCHOOL AND LIBRARY VIEW
+-----+
| CA |
+-----+
|
+------------------------------------------------+
| | | | |
+-----+ +-----+ +-----+ +-------------+ +-----+
| K12 | | CC | | TEC | | LOS ANGELES | | LIB |
+-----+ +-----+ +-----+ +-------------+ +-----+
/ \ /|\ /|\ /|\ /|\
+--------+ +---+ +---+ +--------+ +----------+ +------+
|sch dist| |PVT| |SJC| |WM TRADE| |pvt school| |MALIBU|
+--------+ +---+ +---+ +--------+ +----------+ +------+
/|\ /|\
+--------+ +--------+
|sch name| |sch name|
+--------+ +--------+
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
VIEW OF STATE, REGIONAL, and GENERAL AGENCIES
+-----+
| CA |
+-----+
|
+-------------------------+
| | |
+-------+ +--------+ +-----+
| STATE | |DISTRICT| | GEN |
+-------+ +--------+ +-----+
/|\ /|\ /|\
+--------+ +------+ +---------+
|CALTRANS| |SCAQMD| |domain pk|
---------+ +------+ +---------+
|
+--------+
|TCEW100E|
+--------+
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
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RFC 1480 The US Domain June 1993
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
VIEW OF LOCALITY
+-----+
| CA |
+-----+
|
+-----------------------------------+
| |
+-------------------------+ +----------------+
| LOS ANGELES | | SANTA MONICA |
+-------------------------+ +----------------+
/ | | /|\ | /|\
/ | | | | |
+---+ +--+ +--+ +-----------+ +--+ +---+
|bus| |CI| |CO| | pvt school| |CI| |bus|
+---+ +--+ +--+ +-----------+ +--+ +---+
/\ | |
/ \ | +------------+
/ \ | |HARBOR GUARD|
/ \ | +------------+
+-----+ +-----+ +-----+ +----+
|FIRE | |ADMIN| |PARKS| |FIRE|
+-----+ +-----+ +-----+ +----+
++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++++
2.1 State Codes
The state codes are the two letter US Postal abbreviations. For
example: "CA" California.
2.2 Locality Names
Within the state name space there are "locality" names, some may be
cities, some may be counties, some may be local names, but not
incorporated entities.
Registered names under "locality" could be like:
<hostname>.CI.<locality>.<state>.US ==> city gov't agency
<hostname>.CO.<locality>.<state>.US, ==> county gov't agency
<hostname>.<locality>.<state>.US ==> businesses
In the cases where the locality name is a county, there is a branch
under the locality name, called "county" or "CO", that is used by the
county government. Businesses are registered directly under the
locality name.
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RFC 1480 The US Domain June 1993
Under the city locality name space there is a "city" or "CI" branch
for city government agencies. As usual, businesses and private
schools may register directly under the city name.
In the case where there is both a county and a city with the same
locality name there is no problem, since the names will be unique
with the "CO" or "CI" keyword. In our area the county has a fire
department and the city has its own fire department. They could have
names like:
Fire-Dept.CI.Los-Angeles.CA.US
Fire-Dept.CO.Los-Angeles.CA.US
Cities may be named (designated) by their full name (spelled out with
hyphens replacing spaces (e.g., Los-Angeles or Fort-Collins), or by a
city code. The first choice is the full city name. In some cases it
may be appropriate to use the well-known city abbreviation known
throughout a locality. However, it is very desirable that all users
in the same city use the same designator for the city. That is, any
particular locality should have just one DNS name.
Some users would like names associated with a greater metropolitan
area or region like the "Bay Area" or "Tri-Cities". One problem with
this is that these names are not necessarily unique within a state.
The best thing to do in this case is to use the larger metropolitan
city in your hostname. Cities and counties are used.
Should all the names be obvious? Trying to do this is desirable and
also impossible. There will come a point when the obviously right
name for an organization is already taken. As the system grows this
will happen with increasing frequency. While ease of use to the end
user is desirable, a higher priority must be placed on having a
system that operates. This means that the manageability of the
system must have high consideration.
The reason the DNS was created was to subdivide the problem of
maintaining a list of hosts in the Internet into manageable portions.
The happy result is that this subdivision makes name uniqueness
easier and promotes logical grouping. What is a "logical grouping"
though, always depends on the viewer.
Many levels of delegation are needed to keep the zone files
manageable. Many sections of the name space are needed to allow
unique names to be easily added.
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RFC 1480 The US Domain June 1993
Way back in the olden days, when the Internet was invented, some
thought that an 8-bit network number would be more than enough to
number all the networks that would ever exist. Today, there are over
10,000 networks operating in the Internet, and arguments are made
about the doubling time being 2 years versus 4 years.
One concern is that things will continue to grow dramatically, and
this will require more subdivision of the domain name management.
Maybe the plan for the US Domain is overkill on growth planning, but
there has never been overplanning for growth yet.
When things are bigger, names have to be longer. There is an
argument that with only 8-character names, and in each position allow
a-z, 0-9, and -, you get 37**8 = 3,512,479,453,921 or 3.5 trillion
possible names. It is a great argument, but how many of us want
names like "xs4gp-7q". It is like license plate numbers, sure some
people get the name they want on a vanity plate, but a lot more
people who want something specific on a vanity plate can't get it
because someone else got it first. Structure and longer names also
let more people get their "obviously right" name.
2.3 Schools
K12 schools are connecting to the Internet and registering in the
Internet DNS. A decision has been made by the IANA (after
consultation with the new InterNIC Internet Registry and the Federal
Networking Council (FNC)) to direct these school registrations to the
US domain using the naming structure described here.
There is a need for competent, experienced, volunteers to come
forward to act as third and perhaps fourth level registries and to
operate delegated portions of the DNS.
There are two reasons for registering schools in the US Domain. (1)
uniqueness of names, and (2) management of the database.
1. Name Uniqueness:
There are many "Washington" high schools, only one can be
"Washington.EDU" (actually none can be, since that name is used
by a University. There will be many name conflicts if all
schools attempt to register directly under EDU.
In addition, in some districts, the same school name is used at
different levels, for example, Washington Elementary School and
Washington High School. We suggest that when necessary, the
keywords "Elementary", "Middle", and "High" be used to
distinguish these schools. These keywords would only be used
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RFC 1480 The US Domain June 1993
when they are needed, if the school's name is unique without
such keywords, don't use them.
2. Database Management:
One goal of the DNS is to divide up the management of the name
database in to small pieces. Each piece (or "zone" in DNS
terminology) could be managed by a distinct administrator.
Adding all the high schools to the EDU domain will make the
already large zone file for EDU even larger, possibly to the
point of being unmanageable.
For both these reasons it is necessary to introduce structure into
names. Structure provides a basis for making common names unique in
context, and for dividing the management responsibility.
The US Domain has a framework established and has registered many
schools already in this structured scheme. The general form is:
<school>.<district>.K12.<state>.US.
For example: Hamilton.LA-Unified.K12.CA.US
Public schools are usually organized by districts which can be larger
or smaller than a city or county. For example, the Portland school
district in Oregon, is in three or four counties. Each of those
counties also has non-Portland districts.
It makes sense to name schools within districts. However districts
often have the same name as a city or county so there has to be a way
to distinguish a public school district name from some other type of
locality name. The keyword "K12" is used for this.
For example, typical K12 school names currently used are:
IVY.PRS.K12.NJ.US
DMHS.JCPS.K12.KY.US
OHS.EUNION.K12.CA.US
BOHS.BREA.K12.CA.US
These names are generally longer than the old alternative of shorter
names in the EDU domain, but that would not have lasted long without
a significant number of schools finding that their "obviously
correct" name has already been used by some other school.
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RFC 1480 The US Domain June 1993
When there are many things to name some of the names will be long.
In some cases there may be appropriate abbreviations that can be
used. For example Hamilton High School in Los Angeles could be:
Hami.Hi.LA.K12.CA.US
If a school has a number of PCs, then each PC should have a name.
Suppose they are named "alpha", "beta", ... then if they belong to a
school named "Lincoln.High.Lakewood.K12.CA.US" their names would be:
alpha.Lincoln.High.Lakewood.K12.CA.US.
beta.Lincoln.High.Lakewood.K12.CA.US
...
The K12 subdomain provides two points at which to delegate a branch
of the database to distinct administrators -- the K12 Administrator
for each state, and the district administrator for each district
within a state.
The US Domain Administrator will delegate a branch of the US domain
to an appropriate party. In some cases, this may be a particular
school, a school district, or ever all of K12 for a state.
The responsibility for managing a K12 branch or sub-branch may be
delegated to an appropriate volunteer. We envision that such
delegations of the schools' DNS service may eventually migrate to
someone else "more appropriate" from an administrative organizational
point of view. The "obvious" state agency to manage the schools' DNS
branch may take some time to get up to speed on Internetting. In the
meantime, we can have the more advanced schools up and running.
Special Schools and Service Units
In many states, there are special schools that are not in districts
that are run directly by the state or by consortiums. There are also
service units that provide "educational services" ranging from books
and computers to janitorial supplies and building maintenance. Often
these service units do not have a one-to-one relationship with
districts.
There is some concern about naming these schools and service units
within the naming structure for schools established in this memo.
There are several possibilities. For a state with many service units
creating a "pseudo district" ESU (or whatever, the common terminology
is in that state) is a possibility. For example, the Johnson service
unit could be JOHNSON.ESU.K12.CA.US. For a state with a few such
service units (and avoiding conflicts with district names) the
service units could be directly under K12. For example,
Cooper & Postel [Page 12]
RFC 1480 The US Domain June 1993
TIES.K12.MN.US.
The special public funded schools can be handled in a similar
fashion. If there are many special schools in a state, a "pseudo
district" should be established and all the special schools listed
under it. For example, suppose there is a "pseudo district" in
Massachusetts called SPCL, and there is a special school called the
Progressive Computer Institute, then that school could have the name
PCI.SPCL.K12.MA.US. If there are only a few special schools, they
can be listed directly under K12 (avoiding name conflicts with
district names). For example, the California Academy of Math and
Science is CAMS.K12.CA.US. CAMS is sponsored by seven schools, the
California Department of Education, and a University.
"PVT" Private Schools
Private schools may be thought of as businesses. Public schools are
in districts, and districts provide a natural organizational
structure for naming and delegation. For private schools there are
no districts and they really do operate like businesses. But, many
people are upset to think about their children in a private school
being in a business category and not in K12 with the rest of the
children. To accommodate both public and private schools, in each
state's K12 branch, we've added an artificial district called private
or "PVT". This gives a private school the option of registering like
a business under "locality" or in the PVT.K12.<state-code>.US branch.
For example:
Crossroads.PVT.K12.CA.US
Crossroads-Santa-Monica.CA.US
A public school "Oak High" in the "Woodward" school district in
California would have a name like "Oak-High.Woodward.K12.CA.US".
A private school "Old Trail" in Pasadena, California could have the
<locality> based name "Old-Trail.Pasadena.CA.US" or the private
school base name "Old-Trail.PVT.K12.CA.US".
Some suggest that for private schools instead of a special pseudo
district PVT to use a locality name. One reason to use district
names is that, in time, it seems likely that school district
administrators will take over the operation of the DNS for their
district. One needs to be able to delegate at that branch point.
One implication of delegation is that the delegatee is now in charge
of a chunk of the name space and will be registering new names. To
keep names unique one can't have two different people registering new
things below identically named branches.
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RFC 1480 The US Domain June 1993
For example, if there is a school district named Pasadena and a city
named Pasadena, the branch of the name space PASADENA.K12.CA.US might
be delegated to the administrator of that public school district. If
a private school in Pasadena wanted to be registered in the DNS, it
would have to get the public school district administrator to do it
(perhaps unlikely) or not be in the K12 branch at all (unless there
is the PVT pseudo district).
So, if private schools are registered by
<school>.<locality>.K12.<state-code>.US and public schools are
registered by <school>.<district>.K12.<state-code>.US, there can't be
any locality names that are the same as district names or the
delegation of these will get very tricky later.
If it is all done by locality names rather than district names, and
public and private schools are mixed together, then finding an
appropriate party to delegate the locality to may be difficult.
Another suggestion was that private schools be registered directly
under K12, while public schools must be under a district under K12.
This would require the operator of the K12 branch to register all
districts and private schools himself (checking for name uniqueness),
he couldn't easily delegate the registration of the private schools
to anyone else.
Community Colleges and Technical Schools
To distinguish Community Colleges and Technical/Vocational schools,
the keywords "CC" and "TEC" have been created.
Some School Examples
Hamilton.High.LA-Unified.K12.CA.US <== a public school
Sherman-Oaks.Elem.LA-Unified.K12.CA.US <== a public school
John-Muir.Middle.Santa-Monica.K12.CA.US <== a public school
Crossroads-School.Santa-Monica.CA.US <== a private school
SMCC.CC.CA.US <== a community college
TECMCC.CC.CA.US <== a community college
Brick-and-Basket-Institute.TEC.CA.US <== a technical college
Northridge.CSU.STATE.CA.US <== a state university
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RFC 1480 The US Domain June 1993
2.4 State Agencies
Several states are setting up networks to interconnect the offices of
state government agencies. The hosts in such networks should be
registered under the STATE.<state-code>.US branch.
A US Domain name space has been established for the state government
agencies. For example, in the State of Minnesota, the subdomain is
STATE.MN.US.
State Agencies:
---------------
Senate.STATE.MN.US <== State Senate
MDH.STATE.MN.US <== Dept. of Health
CALTRANS.STATE.CA.US <== Dept. of Transportation
DMV.STATE.CA.US <== Dept. of Motor Vehicles
2.5 Federal Agencies
A federal name space has been established for the federal government
agencies. For example, the subdomain for the Federal Reserve Bank of
Minneapolis is MNPL.FRB.FED.US. Other examples are listed below.
Federal Government Agencies:
---------------------------
Senate.FED.US <==== US Senate
DOD.FED.US <==== US Defense Dept.
USPS.FED.US <==== US Postal Service
VA.FED.US <==== US Veterans Administration
IRS.FED.US <==== US Internal Revenue Service
Yosemite.NPS.Interior.FED.US <==== A Federal agency
2.6 Distributed National Institutes
The "DNI" branch was created directly under the top-level US. This
is to be used for organizations that span state, regional, and other
organizational boundaries; are national in scope, and have
distributed facilities. An example would be:
Distributed National Institutes:
--------------------------------
MetaCenter.DNI.US <==== The MetaCenter Supercomputer Centers
Cooper & Postel [Page 15]
RFC 1480 The US Domain June 1993
The MetaCenter domain encompasses the four NSF sponsored
supercomputer centers. These are:
San Diego Supercomputer Center (SDSC)
National Center for Supercomputing Applications (NCSA)
Pittsburgh Supercomputing Center (PSC)
Cornell Theory Center (CTC)
The MetaCenter Network will enable applications and services like
file systems and archival storage to be operated in a distributed
fashion; thus, allowing the resources at the four centers to appear
integrated and "seamless" to users of the centers.
2.7 General Independent Entities
This name space was created for organizations that don't really fit
anywhere else, such as state-wide associations, clubs, and "domain
parks". Think of this as the miscellaneous category.
The examples are state-wide clubs. For example, the Garden Club of
Arizona, might want to be "GARDEN.GEN.AZ.US". Such a club has
membership from all over the state and is not associated with any one
city (or locality). Another example is "domain parks" that have been
established up-to-now as entities in ORG. For example, there is
"LONESTAR.ORG", which is a kind of computer club in Texas that has
lots of dial-in computers registered. In the US Domain such an
entity might have a name like "LONESTAR.GEN.TX.US".
The organizations registered in GEN may typically be non-profit
entities. These organizations don't fit in a <locality> and are not
a school, library, or state agency. Ordinary businesses are not
registered in GEN.
Some suggest that these kinds of organizations are just like all the
other things and ought to be registered under some <locality>. This
may be true, but sometimes one just can't find any way to convince
the applicant that it is the right thing to do. One can argue that
any organization has to have a headquarters, or an office, or
something about it that is in a fixed place, and thus the
organization could be registered in that place.
Some suggest that no token is needed, these entities could be
directly under the <state-code>. The problem with not having a
token, is that you can't delegate the responsibility for registering
these entities to someone separate from whoever is responsible for
the <state-code>. You want to be able to delegate for both name-
uniqueness reasons, and operational management reasons. Having a
token there makes both easy.
Cooper & Postel [Page 16]
RFC 1480 The US Domain June 1993
General Independent Entities:
-----------------------------
CAL-Comp-Club.GEN.CA.US <==== The Computer Club of California
2.8 Examples of Names
For small entities like individuals or small businesses, there is
usually no problem with selecting locality based names.
For example: Zuckys.Santa-Monica.CA.US
For large entities like large corporations with multiple
facilities in several cities or states this often seems like an
unreasonable constraint (especially when compared with the
alternative of registering directly in the COM domain). However,
a company does have a headquarters office in a particular locality
and so could register with that name. Example: IBM.Armonk.NY.US
PRIVATE (business or individual)
================================
Camp-Curry.Yosemite.CA.US <==== a business
IBM.Armonk.NY.US <==== a business
Dogwood.atl.GA.US <==== a business
Geo-Petrellis.Culver-City.CA.US <==== a restaurant
Zuckys.Santa-Monica.CA.US <==== a restaurant
Joe-Josts.Long-Beach.CA.US <==== a bar
Holodek.Santa-Cruz.CA.US <==== a personal computer
FEDERAL
=======
Senate.FED.US <==== US Senate
DOD.FED.US <==== US Defense Dept.
DOT.FED.US <==== US Transportation Dept.
USPS.FED.US <==== US Postal Service
VA.FED.US <==== US Veterans Administration
IRS.FED.US <==== US Internal Revenue Service
Yosemite.NPS.Interior.FED.US <==== a federal agency
MNPL.FRB.FED.US. <==== US Fed. Reserve Bank of Minneapolis
Cooper & Postel [Page 17]
RFC 1480 The US Domain June 1993
STATE
=====
Senate.STATE.MN.US <==== state Senate
House.STATE.MN.US <==== state House of Reps
MDH.STATE.MN.US <==== state Health Dept.
HUD.STATE.CA.US <==== state House and Urban Dev. Dept.
DOT.STATE.MN.US <==== state Transportation Dept.
CALTRANS.STATE.CA.US <==== state Transportation Dept.
DMV.STATE.CA.US <==== state Motor Vehicles Dept.
Culver-City.DMV.STATE.CA.US <==== a local office of DMV
DNI (distributed national Institutes)
======================================
METACENTER.DNI.US <==== a distributed nat'l Inst.
GEN (General Independent Entities)
==================================
GARDEN.GEN.AZ.US <==== a garden club of Arizona
CITY | CI | COUNTY | CO (locality)
==================================
Parks.CI.Culver-City.CA.US <==== a city department
Fire-Dept.CI.Los-Angeles.CA.US <==== a city department
Fire-Dept.CO.Los-Angeles.CA.US <==== a county department
Planning.CO.Fulton.GA.US. <==== a county department
Main.Library.CI.Los-Angeles.CA.US <==== a city department
MDR.Library.CO.Los-Angeles.CA.US <==== a county department
TOWNSHIP | PARISH (locality)
============================
Police.TOWNSHIP.Green.OH.US <==== a township department
Administration.PARISH.Lafayette.LA.US <==== a parish department
Cooper & Postel [Page 18]
RFC 1480 The US Domain June 1993
DISTRICT | LIBRARY (agency)
============================
SCAQMD.DISTRICT.CA.US <==== a regional district
Bunker-Hill-Improvement.DISTRICT.LA.CA.US <==== a local district
Huntington.LIB.CA.US <==== a private library
Venice.LA-City.LIB.CA.US <==== a city library
MDR.LA-County.LIB.CA.US <==== a county library
K12 | PRIVATE SCHOOLS (PVT) | CC | TEC
======================================
Hamilton.High.LA-Unified.K12.CA.US <==== a public school
Sherman-Oaks.Elem.LA-Unified.K12.CA.US <==== a public K12 school
John-Muir.Middle.Santa-Monica.K12.CA.US <==== a public K12 school
Culver-High.CCSD.K12.CA.US <==== a public K12 school
St-Monica.High.Santa-Monica.CA.US <==== a private school
Crossroads-School.Santa-Monica.CA.US <==== a private school
Mary-Ellens.Montessori-School.LA.CA.US <==== a private school
Progress-Learning-Center.PVT.K12.CA.US <==== a private school
SMCC.Santa-Monica.CC.CA.US <==== a public community college
Trade-Tech.Los-Angeles.CC.CA.US <==== a public community college
Valley.Los-Angeles.CC.CA.US <==== a public community college
Brick-and-Basket-Institute.TEC.CA.US <== a technical college
When appropriate, subdomains are delegated and partioned in
various categories, such as:
<locality>.<state>.US = city/locality based names
K12.<state>.US = kindergarten thru 12th grade
PVT.K12.<state.US = private kindergarten thru 12th grade
CC.<state>.US = community colleges
TEC.<state>.US = technical or vocational schools
LIB.<state>.US = libraries
STATE.<state>.US = state government agencies
<org-name>.FED.US = federal government agencies
<org-name>.DNI.US = distributed national institutes
<org-name>.GEN.<state>.US. = statewide assoc,clubs,domain parks
The Appendix-I contains the current US Domain Names BNF.
Cooper & Postel [Page 19]
RFC 1480 The US Domain June 1993
3. REGISTRATION
There are two types of registrations (1) Delegation, where a branch
of the US Domain is delegated to an organization running name servers
to support that branch; or (2) Direct Registration, in which the
information is put directly into the main database.
In Direct Registration there are two cases: (a) an IP-host (with an
IP address), and (b) non-IP host (for example, a UUCP host). Any
particular registration will involve any one of these three
situations.
3.1 Requirements
Anyone requesting to register a host in the US Domain is sent a copy
of the "Instructions for the US Domain Template", and must fill out a
US Domain template.
The US Domain template, is similar to the InterNIC Domain template,
but it is not the same. To request a copy of the US Domain template,
send a message to the US Domain registrar (us-domain@isi.edu).
If you are registering a name in a delegated zone, please register
with the contact for that zone. You can FTP the file "in-notes/us-
domain-delegated.txt" from venera.isi.edu, via anonymous FTP. This
information is also available via email from RFC-INFO@ISI.EDU
(include as the only text in the message
"Help: us_domain_delegated_domains").
The key people must have electronic mailboxes (that work). Please
provide all the information indicated in the "Administrator" and
"Technical Contact" slots.
The administrator will be the point of contact for any administrative
and policy questions about the domain. The administrator is usually
the person who manages the organization being registered.
The technical contact can also be administrator, or the systems
person, or someone who is familiar with the technical details of the
Internet. The technical contact should have a valid working email
address. This is necessary in case something goes wrong.
It is important that your "Return-Path" and "From" field indicate an
Internet-style address. UUCP-style addresses such as "host1!user"
will not work. This is fine within the UUCP world, but not the
Internet. If you want people on the Internet to be able to send mail
to you, your return path needs to be an Internet-style address such
as: host1!user@Internet.gateway.host or user@Internet.gateway.host.
Cooper & Postel [Page 20]
RFC 1480 The US Domain June 1993
It is also possible to register through one of the Internet service
providers that have established working relationships with the US
Domain Administrator.
If everything checks out, the turn around time for registering a host
is usually a few days. The name servers are updated anywhere from 12
to 24 hours later.
There are two ways to be registered in the US Domain, directly, or by
delegation.
3.2 Direct Entries
Direct entry in the database of the US Domain appeals most to
individuals and small companies. You may fill out the application
and send it directly to the US Domain Administrator. If you are in
an area where the zone is delegated to someone else your request will
be forwarded to the zone administrator for your registration. Or,
you may send the form directly to the manager of a delegated zone
(see Section 3.1).
3.2.1 IP-Hosts
These are hosts with IP addresses which correspond to "A" records in
the DNS database.
3.2.2 Non-IP Hosts
Many applicants have hosts in the UUCP world. Some are one hop away,
some two and three hops away from their "Internet Forwarder", this is
acceptable. What is important is getting an Internet host to be your
forwarder. If you do not already have an Internet forwarder, there
are several businesses that provide this service for a fee, such as
UUNET.UU.NET (postmaster@uunet.uu.net), PSI (postmaster@UU2.PSI.COM)
and CERFNET (help@cerf.net). Sometimes local colleges in your area
are already on the Internet and may be willing to act as an Internet
Forwarder. You would need to work this out with the systems
administrator as we cannot make these arrangements for you.
Although we work with UUCP service providers, the Internet US Domain
registration is not affiliated with the registration of UUCP Map
entries. The UUCP map entry does not provide us with sufficient
information. If you do not have a copy of the US Domain
questionnaire template, please send a message to: us-domain@isi.edu
and request one. See Appendix-II.
Cooper & Postel [Page 21]
RFC 1480 The US Domain June 1993
The example below is not an appropriate registration for the US Domain.
#N starl
#S Amiga 2500; AmigaDOS 2.04; Dillon's AmigaUUCP 1.15D
#O Starlight BBS
#C Stephen Baker
#E starl!sbaker
#T +1 305 378 1161
#P 1107 SW 200th St #303B Miami, Fl. 33157
#L 25 47 N / 88 10 W [city]
#R
#U mthvax
#W starl!sbaker (Stephen Baker); Mon Feb 24 19:58:24 EST 1992
starl mthvax(DAILY)
If you are registering your host as a central site for a USENET group
where other UUCP sites will feed from you, that's fine. These UUCP
sites do not need to register. If however, the other sites become a
subdomain of your hostname, then we will need to register them
individually or add a wildcard record. (See Section 4.4. Wildcards).
For example: bah.rochester.ny.us
host1.bah.rochester.ny.us
host2.bah.rochester.ny.us
To use US Domain names for non-IP hosts, there must be a forwarder
host that is an IP host. There must be an administrative agreement
and a technical procedure for relaying mail between the non-IP host
and the forwarder host.
Case 1:
-------
Your host is not an IP host but does talk directly with a host that
is an IP host.
+-----------------+
+----------+ +---------+ | |
|your-host |---UUCP-----|forwarder|----IP/TCP--| INTERNET |
+----------+ +---------+ | |
+-----------------+
"Forwarder" must be an IP host on the Internet.
You must ask "forwarder" if they are willing to be the Internet
forwarder for "your-host".
In the US Domain of the DNS data base there must be an entry like
this:
"your-host" MX 10 "forwarder"
Cooper & Postel [Page 22]
RFC 1480 The US Domain June 1993
This must be entered by the US Domain Administrator.
In the "forwarder" routing tables there must be information about
"your-host" with a rule like: If I see mail for "your-host" I will
send it via uucp by calling phone number "123-4567".
Case 2:
-------
In this case your hosts talks to another host that ... that talks to
an IP host. In other words, there are multiple hops between your host
and the Internet.
+-----------------+
+----------+ +---------+ | |
|path-host |---UUCP-----|forwarder|----IP/TCP--| INTERNET |
+----------+ +---------+ | |
| +-----------------+
UUCP
|
+----------+
|your-host |
+----------+
"Forwarder" must be an IP host on the Internet.
You must ask "forwarder" if they are willing to be the Internet
Forwarder for "Your-Host". You must ask "path-host" to relay your
mail.
In the US Domain of the DNS Database there must be an entry like this:
"your-host" MX 10 "forwarder"
This must be entered by the US Domain Administrator.
In the "forwarder" routing tables there must be information about
"your-host" with a rule like: If I see mail for "your-host" I will
send it via UUCP to "path-host" by calling phone number "123-4567".
and "path-host" must also know how to relay the mail to "your-host".
Note: It is assumed that "path-host" is already MXed to "forwarder".
It is not appropriate to ask to MX "your-host" to "path-host" (this
is sometimes called double MXing). The host on the right hand side
of an MX entry must be a host on the Internet with an IP address
(e.g., 128.9.2.32).
Cooper & Postel [Page 23]
RFC 1480 The US Domain June 1993
3.3 Delegated Subdomains
Many branches of the US Domain are delegated. There must be a
knowledgeable and competent technical contact, familiar with the
Internet DNS. This requirement is easily satisified if the technical
contact already runs some other name servers.
Examples of delegations are K12.TX.US for the Kindergarten through
12th Grade public schools in Texas, the locality "berkeley.ca.us", or
the LIB.MN.US branch for the libraries in Minnesota.
The administrator of the US Domain is responsible for the assignment
of all the DNS names that end with ".US". Of course, one person or
even one group can't handle all this in the long run so portions of
the name space are delegated to others.
The major concern in selecting a designated manager for a domain is
that it be able to carry out the necessary responsibilities, and have
the ability to do an equitable, just, honest, and competent job.
The key requirement is that for each domain there be a designated
manager for supervising that domain's name space.
These designated authorities are trustees for the delegated domain,
and have a duty to serve the community.
The designated manager is the trustee of the domain for the domain
itself and the global Internet community.
Concerns about "rights" and "ownership" of domains are inappropriate.
It is appropriate to be concerned about "responsibilities" and
"service" to the community.
The designated manager must be equitable to all groups in the domain
that request domain names.
This means that the same rules are applied to all requests. All
requests must be processed in a nondiscriminatory fashion, and
academic and commercial (and other) users are treated on an equal
basis. No bias shall be shown regarding requests that may come from
customers of some other business related to the manager -- e.g., no
preferential service for customers of a particular data network
provider. There can be no requirement that a particular mail system
(or other application), protocol, or product be used.
There are no requirements on subdomains beyond the requirements on
higher-level domains themselves. That is, the requirements are
applied recursively. In particular, all subdomains shall be allowed
Cooper & Postel [Page 24]
RFC 1480 The US Domain June 1993
to operate their own domain name servers, providing in them whatever
information the subdomain manager sees fit (as long as it is true and
correct).
Significantly interested parties in the domain should agree that the
designated manager is the appropriate party.
The US Domain Administrator tries to have any contending parties
reach agreement among themselves, and generally takes no action to
change things unless all the contending parties agree; only in cases
where the designated manager has substantially neglected their
responsibilities would the US Domain Administrator step in.
The designated manager must do a satisfactory job of operating the
DNS service for the domain.
That is, the actual management of the assigning of domain names,
delegating subdomains and operating name servers must be done with
technical competence. This includes keeping the US Domain
Administrator or other higher-level domain managers advised of the
status of the domain, responding to requests in a timely manner, and
operating the database with accuracy, robustness, and resilience.
There must be a primary and a secondary name server that have IP
connectivity to the Internet and can be easily checked for
operational status and database accuracy by the US Domain
Administrator.
One of the aspects of having two name servers for each domain (or
zone), is for robustness. One concern under this heading is that the
name service not go out entirely if there is a local power failure
(earthquake, tornado, or other disaster).
Name Servers should be in distinctly separate physical locations. It
is appropriate to have more than two name servers, but there must be
at least two.
For any transfer of the designated manager trusteeship from one
organization to another, the higher-level domain manager must receive
communications from both the old organization and the new
organization that assures the US Domain Administrator that the
transfer in mutually agreed, and that the new organization
understands its responsibilities.
It is also very helpful for the US Domain Administrator to receive
communications from other parties that may be concerned or affected
by the transfer.
Cooper & Postel [Page 25]
RFC 1480 The US Domain June 1993
Delegation of cities, companies within cities, schools (K12),
community colleges (CC), libraries (LIB), state government (STATE),
and federal government agencies (FED), etc., is acceptable and
practical.
For a delegated portion of the name space, for example a city, no
alterations can be made to that name, no abbreviations added, etc.
unless applied for.
Sometimes there may be two people running name servers in the same
city because different portions of the name space has been delegated
to them. For example, someone may be delegated the <city>.<state>.US
name space, and someone else from a state government agency may have
the .STATE.<state>.US, portion. For example, Fred may run the name
servers for Sacramento.CA.US and Joe may run the name servers for
STATE.CA.US in Sacramento.
If a company would like to have wildcard records added, or run their
own name servers in a city that we have delegated name space to, this
is acceptable.
Delegation of the whole State name space is not yet implemented. The
delegated part of the name space is in the form of:
.<locality>.<state>.US.
.CI.<locality>.<state>.US.
.CO.<locality>.<state>.US.
.STATE.<state>.US.
.K12.<state>.US.
PVT.K12.<state>.US.
.CC.<state>.US.
.TEC.<state>.US.
.LIB.<state>.US.
.GEN.<state>.US.
.DNI.US.
.FED.US.
3.3.1. Delegation Requirements
When a subdomain is delegated, the following requirements must be
met:
1) There must be a knowledgeable and competent technical contact,
familiar with the Internet DNS. This requirement is easily
satisified if the technical contact already runs some other
name servers.
Cooper & Postel [Page 26]
RFC 1480 The US Domain June 1993
2) Organizations requesting delegations must provide at least two
independent (robust and reliable) DNS name servers in
physically separate locations on the Internet.
3) The subdomain must accept all applicants on an equal basis.
4) The subdomain must provide timely processing of requests. To
do this, it is helpful to have several individuals
knowledgeable about the procedures so that the operations are
not delayed due to one persons unavailability (for example, by
being on vacation).
5) The subdomain manager must tell the US Domain Administrator
when there are changes in the name servers that should be
reflected in the US Domain zone files, or changes in the
contact information.
K12 Administrators
In the long term, registering schools will be a big job. So you
need to have in mind delegating parts of the work to various
school districts. If you can delegate every school district in
the state then you are finished, except for checking that they are
all operating correctly. However, initially you will have quite a
bit to do with educating people, helping them choose names and
getting name servers arranged. You are responsible for seeing
that the naming of schools follow the guidelines suggested in this
memo.
All K12 Administrators will initially be responsible for managing
the "pseudo district" PVT for private schools. Private schools
have the option of registering as <school-name>.PVT.K12.<state>.US
or as a business under the city based names.
Locality Administrators
If you have been delegated a locality subdomain, you will be
responsible for registering not only businesses directly under the
locality, but city and county agencies under the "CI" and "CO"
branches. When appropriate these branches should be delegated.
If you want, you may spell out "CITY" instead of "CI" or "COUNTY"
instead of "CO", but you must be consistent and use only one or
the other in a given locality. The whole city government should
be under one branch.
Cooper & Postel [Page 27]
RFC 1480 The US Domain June 1993
WHOIS Database
Only the second and third level delegated name spaces will be
entered in the WHOIS database. For example, K12.CA.US would have
an entry in WHOIS. Anything under K12.CA.US will not be listed.
The US Domain Administrator will send the information that you
supplied on your US Domain template to the InterNIC. It is the
hope that in the future, each delegated subdomain will provide
their own WHOIS directory database for their branch.
3.3.2 Delegation Procedures
The procedure that is followed when a subdomain is delegated includes
the following steps:
1) Evaluate the technical contact's experience with DNS. Make
sure there is a need for the proposed delegation. Make sure
the technical contact has the information about the US Domain
and the suggested naming structure. Two contacts with email
addresses are necessary in case something goes wrong.
2) Add the new technical contact to the "us-dom-adm" mailing list
for distributing updates concerning the US Domain policies and
procedures.
3) Delete any hosts from our zone file that belongs in the newly
delegated subdomain and make sure they now have the hosts in
their zone file.
4) Send them a copy of the zone file so their initial zone file
is identical to ours. For example:
mil.wi.us. 69582 SOA spool.mu.edu.
manager.spool.mu.edu. (
930119 ;serial
28800 ;refresh
14400 ;retry
3600000 ;expire
86400 ) ;minim
mil.wi.us. 69582 NS spool.mu.edu.
spool.mu.edu. 85483 A 134.48.1.31
mil.wi.us. 69582 NS sophie.mscs.mu.edu.
sophie.mscs.mu.edu. 85483 A 134.48.4.6
solaria.mil.wi.us. 69582 HINFO Sun 3/60 SunOs
solaria.mil.wi.us. 69582 MX 10 spool.mu.edu.
nthomas.mil.wi.us. 69582 HINFO 386 Clone DOS
nthomas.mil.wi.us. 69582 MX 10 spool.mu.edu.
Cooper & Postel [Page 28]
RFC 1480 The US Domain June 1993
rwmke.mil.wi.us. 69582 HINFO UNIX PC UNIX
rwmke.mil.wi.us. 69582 MX 10 spool.mu.edu.
milestn.mil.wi.us. 69582 MX 10 spool.mu.edu.
nrunner.mil.wi.us. 69582 HINFO MacIntosh System 7
nrunner.mil.wi.us. 69582 MX 10 spool.mu.edu.
dawley.mil.wi.us. 69582 HINFO 386 Clone DOS
dawley.mil.wi.us. 69582 MX 10 spool.mu.edu.
...
5) The US Domain zone file must have the following records,
showing the name, address, email, and phone number of the
technical contact for the delegated subdomain and the name of
the delegated name space and the names of the name servers.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
;
;Contact: Joseph Klein (tjk@spool.mu.edu)
; Marquette University
; (414) 288-6734
;
;Delegate mil.wi.us zone
mil.wi.us. 604800 NS SPOOL.MU.EDU.
604800 NS SOPHIE.MSCS.MU.EDU.
; A glue record is not needed this time. Glue records are
; needed when the name of the server is a subdomain of the
; delegated domain.
;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;;
6) Check to see that delegated subdomain name servers are up and
running, and make sure the delegated hosts are installed in
their zone file. Now delete any hosts from the US Domain zone
file that belongs in the newly delegated subdomain.
7) Inform the technical contact of the newly delegated subdomain
that wildcard records are allowed in the zone file under the
organizational subdomain but no wildcard records are allowed
under the "city" or "state" domain.
8) Make sure each administrator has a copy of this RFC and
follows the guidelines set forth.
3.3.3 Subdomain Contacts
The number of hosts registered under each subdomain is unknown. See
Section 3.1 for information on the delegated domains and the
contacts.
Cooper & Postel [Page 29]
RFC 1480 The US Domain June 1993
4. DATABASE INFORMATION
4.1. Name Servers
Name servers are the repositories of information that make up the
domain database. The database is divided up into sections called
zones, which are distributed among the name servers. While name
servers can have several optional functions and sources of data, the
essential task of a name server is to answer queries using data in
its zones. The response to a query can always be generated using
only local data, and either contains the answer to the question or a
referral to other name servers "closer" to the desired information.
A given zone will be available from several name servers to insure
its availability in spite of host or communication link failure.
Every zone is required to be available on at least two servers, and
many zones have more redundancy than that.
The US Domain is currently supported by seven name servers:
venera.isi.edu
ns.isi.edu
rs.internic.net
ns.csl.sri.com
ns.uu.net
adm.brl.mil
excalibur.usc.edu
4.2 Zone Files
A "zone" is a registry of domains kept by a particular organization.
A zone registry is "authoritative", that is, the master copy of the
registry is kept by the zone organization, and this copy is, by
definition, always up-to-date. Copies of this registry may be
distributed to other places and kept in caches, but these caches are
not authoritative, and may be out-of-date.
Every zone has at least one node, and hence domain name, for which it
is authoritative, and all of the nodes in a particular zone are
connected. Given the tree structure, every zone has a highest node
which is closer to the root than any other node in the zone. The
name of this node is often used to identify the zone. The data that
describes a zone has four major parts:
1) Authoritative data for all nodes within the zone.
2) Data that defines the top node of the zone
(can be thought of as part of the authoritative data).
Cooper & Postel [Page 30]
RFC 1480 The US Domain June 1993
3) Data that describes delegated subzones, i.e., cuts
around the bottom of the zone,
4) Data that allows access to name servers for subzones
(sometimes called "glue" data).
The zone administrator has to maintain the zones at all the name
servers which are authoritative for the zone. When the changes are
made, they must be distributed to all of the name servers.
Copies of the zone files are not available unless you are on the
Internet. To look at the zone files use the "dig" program of the DNS
domain name system.
dig @nshost host-your-checking axfr
4.3 Resource Records
Records in the zone data files are called resource records (RRs).
The standard Resource records (RR) are specified in STD 13, RFC 1034
and STD 13, RFC 1035 (3,4). An RR has a standard format as shown.
<name> [<ttl>] [<class>] <type> <data>
The first field is always the name of the domain record. The second
field is an optional time to live field. This specifies how long
this data will be stored in the data base. The third field is the
address class; the class field specifies the protocol group most
often this is the Internet class "IN". The fourth field states the
type of the resource record. The fields after that are dependent on
the Type of RR. The fifth field is the data field which is defined
differently for each type and class of data. Here is a list of the
current commonly used types:
SOA Start of Authority
NS Name Server
A Internet Address
CNAME Canonical Name (nickname pointer)
HINFO Host Information
WKS Well Known Services
MX Mail Exchanger
PTR Pointer
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RFC 1480 The US Domain June 1993
What do the fields mean?
foo.LA.CA.US. 604800 MX 10 Venera.ISI.EDU.
(1) (2) (3) (4) (5)
1) domain name
2) time to live information
3) mail exchanger record
4) preference value to determine (if more than one
forwarder) which mailer to use first, lower number
higher preference
5) the Internet forwarding host.
4.3.1 "A" Records
Internet (IP) Address. The data for an "A" record is an Internet
address in a dotted decimal form. A sample "A" record might look
like:
venera.isi.edu. A 128.9.0.32
(name) (A) (address)
The name field is the machine name, and the address is the network
address. There should be only one "A" record for each address of a
host.
4.3.2 CNAME Records
Canonical Name resource record, CNAME, specifies an alias for a
canonical name. This is essentially a pointer to the official name
for the requested name. All other RRs appear under this official
name. A machine named FERNWOOD.MPK.CA.US may want to have the
nickname ANTERIOR.MPK.CA.US. In that case, the following RR would be
used:
anterior.mpk.ca.us. CNAME fernwood.mpk.ca.us.
(alias nickname) (canonical name)
Nicknames (the name associated with the RR is the nickname) may be
added for awhile when a host changes its name, usually because it
moves to another state. It helps to have this CNAME pointer so if
any mail comes to the old address it will get forwarded to the new
one. There cannot be any other RRs associated with a nickname of the
same class.
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RFC 1480 The US Domain June 1993
4.3.3 MX Records
Mail Exchanger records, MX, are used to specify a machine that knows
how to deliver mail to a machine that is not directly connected to
the Internet. For example, venera.isi.edu is the mail gateway that
knows how to deliver mail to foo.la.ca.us, but other machines on the
network cannot deliver mail directly to foo.la.ca.us. These two
machines may have a private connection or use a different transport
medium (such as uucp). The preference value (10) is the order that a
mailer should follow when there is more than one way to deliver mail
to a single machine. The lower the number the higher the preference.
foo.LA.CA.US. 604800 MX 10 Venera.ISI.EDU.
foo.LA.CA.US. 604800 MX 20 relay1.uu.net.
4.3.4 HINFO Records
Host information resource records, HINFO is for host specific data.
This lists the hardware and operating system that are running at the
listed host. It should be noted that a space separates the hardware
information and the operating system information. If you want to
include a space in the machine name you must quote the name. Host
information is not specific to any class, so ANY may be used for the
address class. There should be one HINFO record for each host.
acb.la.ca.us. HINFO VAX-11/780 UNIX
(Hardware) (Operating System)
The official HINFO types can be found in the latest Assigned Numbers
RFC, the most recent edition being STD 2, RFC 1340 [9]. The hardware
type is called the Machine Name, and the software type is called the
System Name.
The information users supply about this is often inconsistent or
incomplete. Please follow the terms in the current "Assigned
Numbers".
4.3.5 PTR Records
A Domain Name Pointer record, PTR, allows special names to point to
some other location in the domain data base. These are typically
used in setting up reverse pointers for the special IN-ADDR.ARPA
domain. PTR names should be unique to the zone.
0.0.9.128.in-addr.arpa PTR isi-net.isi.edu.
(special name) (real name)
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RFC 1480 The US Domain June 1993
A PTR record is to be added to the IN-ADDR.ARPA domain for every "A"
record registered in the US Domain. These PTR records need to be
added by the administrator of the network where the host is
connected. The US Domain Administration does not administer the
network and cannot make these entries in the DNS database.
4.4 Wildcards
The wildcard records are of the form "*.<anydomain>", where
<anydomain> is any domain name. The wildcards potentially apply to
descendents of <anydomain>, but not to <anydomain> itself.
For example, suppose a large company located in California with a
large, non-IP/TCP, network wanted to create a mail gateway. If the
company was called DWP.LA.CA.US, and the IP/TCP capable gateway
machine (Internet forwarder) was called ELROY.JPL.NASA.GOV, the
following RRs might be entered into the .US zone.
dwp.la.ca.us MX 10 ELROY.JPL.NASA.GOV
*.dwp.la.ca.us MX 10 ELROY.JPL.NASA.GOV
The wildcard record *.DWP.LA.CA.US would cause an MX query for any
domain name ending in DWP.LA.CA.US to return an MX RR pointing at
ELROY.JPL.NASA.GOV. The entry without the "*" is needed so the host
dwp can be found.
In the US Domain, wildcard records are allowed in our zone files
under the organizational subdomain (and where noted otherwise) but no
wildcard records are allowed under the "City" or "State" domain.
The authors strongly believe that it is in everyone's
interest and good for the Internet to have each host
explicitly registered (that is, we believe that wildcards
should not be used), we also realize that not everyone
agrees with this belief. Thus, we will allow wildcard
records in the US Domain under groups or organizations.
For example, *.DWP.LA.CA.US.
The reason we feel single entries are the best is by the mere
fact that if anyone wanted to find one of the hosts in the
domain name system it would be there, and problems can be
detected more easily. When using wildcards records all the
hosts under a subdomain are hidden.
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RFC 1480 The US Domain June 1993
5. REFERENCES
[1] Stahl, M., "Domain Administrators Guide", RFC 1032, SRI
International, November 1987.
[2] Lottor, M., "Domain Administrators Operations Guide" RFC 1033,
SRI International, November 1987.
[3] Mockapetris, P., "Domain Names - Concepts and Facilities",
STD 13, RFC 1034, ISI, November 1987.
[4] Mockapetris, P., "Domain Names - Implementation and
Specification", STD 13, RFC 1035, ISI, November 1987.
[5] Dunlap, K., "Name Server Operations Guide for Bind,
Release 4.3", UC Berkeley, SMM:11-3.
[6] Partridge, C., "Mail Routing and the Domain Name System",
STD 14, RFC 974, BBN, January 1986.
[7] Albitz, P., C. Liu, "DNS and Bind" Help for UNIX System
Administrators, O'Reilly and Associates, Inc., October 1992.
[8] ACM SIGUCCS Networking Taskforce, "Connecting to the Internet -
What Connecting Institutions Should Anticipate", FYI 16,
RFC 1359, August 1992.
[9] Reynolds, J., and J. Postel, "Assigned Numbers", STD 2,
RFC 1340, ISI, July 1992.
6. Security Considerations
Security issues are not discussed in this memo.
Cooper & Postel [Page 35]
RFC 1480 The US Domain June 1993
7. Authors' Addresses
Ann Cooper
USC/Information Sciences Institute
4676 Admiralty Way
Marina del Rey, CA 90292
Phone: 1-310-822-1511
Email: cooper@isi.edu
Jon Postel
USC/Information Sciences Institute
4676 Admiralty Way
Marina del Rey, CA 90292
Phone: 1-310-822-1511
Email: postel@isi.edu
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RFC 1480 The US Domain June 1993
APPENDIX-I: US DOMAIN NAMES BNF
================================
<us-domain-name> ::= <us-name><dot><us>
<us-name> ::= <state-name><dot><state-code> |
<fed-name><dot><fed>
<dni-name><dot><dni>
<state-code> ::= <the two-letter code of a state from the
zip code directory>
<state-name> ::= <local-name><dot><locality> |
<state-agency-name><dot><state> |
<regional-agency-name><dot><agency>
<fed-name> ::= <the dotted hierarchical name of a US
federal government agency>
<dni-name> ::= <the dotted hierarchical name of a
distributed national institution>
<locality> ::= <the full name of a city from the
zip code directory> |
<a short code name for a city> |
<the full name of a county, township,
or parish> |
<other well known and commonly used
locality name>
<local-name> ::= <entity-name> |
<city-name><dot><city> |
<county-name><dot><county> |
<local-agency-name><dot><local-agency>
<state-agency-name> ::= <the dotted hierarchical name of a state
government agency>
<regional-agency-name> ::= <the dotted hierarchical name of a
special agency or district not an
element of the state government and
typically larger than a single city or
county, for example, the Southern
California Air Quality Management District>
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RFC 1480 The US Domain June 1993
<entity-name> ::= <the dotted hierarchical name of an
entity within a city, for example: a
company, business, private school, club,
organization, or individual>
<city-name> ::= <the dotted hierarchical name of a city
government agency>
<county-name> ::= <the dotted hierarchical name of a county,
township, or parish government agency>
<local-agency-name> ::= <the dotted hierarchical name of a special
agency or district not an element of a
city or county government and typically
equal or smaller than a single city or
county, for example, the Bunker Hill
Improvement District>
<city> ::= "CI" | "CITY"
<county> ::= "CO" | "COUNTY" | "TOWNSHIP" | "PARISH"
<dot> ::= "."
<fed> ::= "FED"
<dni> ::= "DNI"
<state> ::= "STATE" | "COMMONWEALTH"
<agency> ::= "AGENCY" | "DISTRICT" | "K12" | "CC" | "LIB" |
"GEN" | "TEC"
<local-agency> ::= "AGENCY" | "DISTRICT"
<us> ::= "US"
Notes:
Within States:
"K12" may be used for public school districts. A special name
"PVT" can be used in the place of a school district name for
private schools.
"CC" may be used only for public community colleges.
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RFC 1480 The US Domain June 1993
"LIB" may be only used by libraries.
"TEC" is used only for technical and vocational schools and colleges.
"GEN" is for general independent entities, that is, organizations
that don't really fit anywhere else (such as statewide associations,
clubs, and "domain parks").
"STATE" may be used only for state government entities.
Below US, parallel to States:
"FED" is for agencies of the federal government.
"DNI" is for distributed national institutes; organizations that
span state, regional, and other organizational boundaries; that
are national in scope, and have distributed facilities.
Examples:
=========
Geo-Petrellis.Culver-City.CA.US <== resturant
Joe-Josts.Long-Beach.CA.US <== bar
IBM.Armonk.NY.US <== business
Camp-Curry.Yosemite.CA.US <== business
Yosemite.NPS.Interior.FED.US <== federal agency
Senate.FED.US <== US Senate
DOD.FED.US <== US Defense Dept.
DOT.FED.US <== US Transportation Dept.
MNPL.FRB.FED.US <== the Minneapolis branch of
the Federal Reserve Bank
MetaCenter.DNI.US <== distributed Nat'l Inst
Senate.STATE.MN.US <== state Senate
House.STATE.MN.US <== state House of Reps
Assembly.STATE.CA.US <== state Assembly
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RFC 1480 The US Domain June 1993
MDH.STATE.MN.US <== state Health Dept.
DOT.STATE.MN.US <== state Transportation Dept
CALTRANS.STATE.CA.US <== state Transportation Dept
DMV.STATE.CA.US <== state Motor Vehicles Dept
Culver-City.DMV.STATE.CA.US <== local office of DMV
Police.CI.Culver-City.CA.US <== city department
Fire-Dept.CI.Los-Angeles.CA.US <== city department
Fire-Dept.CO.Los-Angeles.CA.US <== county department
Main.Library.CI.Los-Angeles.CA.US <== city department
MDR.Library.CO.Los-Angeles.CA.US <== county department
Huntington.LIB.CA.US <== private library
SMCC.Santa-Monica.CC.CA.US <== public community college
Trade-Tech.Los-Angeles.CC.CA.US <== public community college
Valley.Los-Angeles.CC.CA.US <== public community college
Hamilton.High.LA-Unified.K12.CA.US <== public school
Sherman-Oaks.Elem.LA-Unified.K12.CA.US <== public school
John-Muir.Middle.Santa-Monica.K12.CA.US <== public school
St-Monicas.High.Santa-Monica.CA.US <== private school
Crossroads-School.Santa-Monica.CA.US <== private school
Mary-Ellens-Montessori-School.LA.CA.US <== private school
Progress-Learning-Center.PVT.K12.CA.US <== private school
Brick-and-Basket-Institute.TEC.CA.US <== technical college
Bunker-Hill.DISTRICT.Los-Angeles.CA.US <== local district
SCAQMD.DISTRICT.CA.US <== regional district
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RFC 1480 The US Domain June 1993
Berkeley.UC.STATE.CA.US <== "CAL"
Los-Angeles.UC.STATE.CA.US <== UCLA
Irvine.UC.STATE.CA.US <== UC Irvine
Northridge.CSU.STATE.CA.US <== CSUN
Los-Angeles.CSU.STATE.CA.US <== Cal State LA
Leland-Stanford-Jr-University.Stanford.CA.US <== private school
~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
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RFC 1480 The US Domain June 1993
APPENDIX-II: US DOMAIN QUESTIONNAIRE FOR HOST ENTRY
To register a host in the US domain, the US Domain Template must be
sent to the US Domain Registrar (US-Domain@ISI.EDU). The first few
pages explain each question on the attached template. FILL OUT THE
TWO PAGE TEMPLATE AT THE END. Questions may be sent by electronic
mail to the above address, or by phone to Ann Cooper, USC/Information
Sciences Institute, (310) 822-1511.
(1) Please specify whether this is a new application, modification to
an existing registration, or deletion.
(2) The name of the domain. This is the name that will be used in
tables and lists associating the domain with the domain server
addresses. See RFC 1480 - The US Domain for more details.
<host>.<city/locality>.<state>.US. = city/locality based names
<school>.<district>.K12.<state>.US. = kindergarten thru 12th grade
<school>.PVT.K12.<state>.US. = private K thru 12th grade
<school>.<locality>.<state>.US. = PVT sch opt: locality names
<school>.CC.<state>.US. = community colleges
<school>.TEC.<state>.US. = technical or vocational schools
<lib-name>.LIB.<state>.US. = libraries
<org-name>.STATE.<state>.US. = state government agencies
<org-name>.FED.US. = federal government agencies
<org-name>.DNI.US. = distributed national institutes
<org>.GEN.<state>.US. = statewide assoc,clubs,domain parks
For example: networthy.santa-clara.ca.us.
(3) The name of the entity represented, that is, the organization
being named. For example: The Networthy Corporation. Not the
name of the organization submitting the request.
(4) Please describe the domain briefly.
For example: The Networthy Corporation is a consulting
organization of people working with UNIX and the C language
in an electronic networking environment. It sponsors two
technical conferences annually and distributes a bimonthly
newsletter.
(5) The date you expect the domain to be fully operational.
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RFC 1480 The US Domain June 1993
For every registration, we need both the Administrative and the
Technical contacts of a domain (questions 6 & 7) and we MUST have a
network mailbox for each. If you have a NIC handle (a unique NIC
database identifier) please enter it. (If you don't know what a NIC
handle is leave it blank). Also the title, mailing address, phone
number, organization, and network mailbox.
(6) The name of the administrative head of the "organization". The
administrator is the contact point for administrative and policy
questions about the domain. The Domain administrator should work
closely with the personnel he has designated as the "technical
contact" for his domain. In this example the Domain Administrator
would be the Administrator of the Networthy Corporation, not the
Administrator of the organization running the name server
(unless it is the same person).
(7) The name of the technical and zone contact. The technical and
zone contact handles the technical aspects of maintaining the
domain's name server and resolver software, and database files.
He keeps the name server running. More than likely, this person
would be the technical contact running the primary name server.