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Network Working Group A. Cooper Request for Comments: 1386 J. Postel

                                                         December 1992
                           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

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 ............................................  5
     2.2  City Codes or Locality Names............................  5
     2.3  Examples of Names.......................................  5
 3.  Registration ................................................  8
     3.1  Requirements ...........................................  8
     3.2  Direct Entries .........................................  9
     3.2.1   UUCP Hosts ..........................................  9
     3.2.2   Non-IP Hosts ........................................ 10
     3.3  Delegated Subdomains ................................... 12
     3.3.1   Schools ............................................. 12
     3.3.2   State Agencies ...................................... 14
     3.3.3   Federal Agencies .................................... 14
     3.3.4   Delegation Requirement............................... 14
     3.3.5   Delegation Procedures ............................... 15
     3.3.6   Subdomain Contacts................................... 18
 4.  Database Information......................................... 19
     4.1  Name Servers ........................................... 19
     4.2  Zone files ............................................. 20
     4.3  Resource Records ....................................... 21
     4.3.1   A Records ........................................... 22
     4.3.2   CNAME Records ....................................... 22
     4.3.3   MX Records .......................................... 22
     4.3.4   HINFO Records ....................................... 23
     4.3.5   PTR Records ......................................... 23
     4.4  Wildcards .............................................. 23
 5.  References .................................................. 24
 6.  Security Considerations ..................................... 25
 7.  Author's Address ............................................ 25
 Appendix-I:  US Domain Names BNF................................. 26
 Appendix-II: US Domain Questionnaire for Host Entry.............. 28

Cooper & Postel [Page 1] RFC 1386 The US Domain December 1992


 1.1 The Internet Domain Name System
 The Domain Name System (DNS) provides for the translation between
 host names and addresses.  Within the Internet, this means
 translating from a name such as "", to an IP address
 such as "".  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 assigned by the Network Information Center
 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 registration point to an Internet
 host (one with an IP address) that acts as a mail forwarder for the
 registered host.  For example, the host "" is
 registered in the DNS with a pointer to the mail relay
 "".  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 host name to address mappings were maintained by the
 Network Information Center (NIC) in a single file, called HOSTS.TXT,
 which was FTPed by all the hosts on the Internet.  The network
 population was changing in character.  The timeshared 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 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 hierarcy levels.  A design using a
 distributed database and generalized resources was implemented.
 The domain system provides standard formats for resource data,

Cooper & Postel [Page 2] RFC 1386 The US Domain December 1992

 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.
 Even though the intention was that any educational institution any
 where 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, similiary 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 it's own way about organizing its domain, and many
 Their are no plans of putting all of the organizational domains .EDU
  .GOV .COM etc., under .US.
 However, there are some states registered in the .GOV domain (11 by 2
 letter code), and 3 by full names)
 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 ".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.

Cooper & Postel [Page 3] RFC 1386 The US Domain December 1992

 1.3  The US Domain
 The US Domain is an official top-level domain in the DNS of the
 Internet community.  It is registered with the Network Information
 Center.  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 NIC 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
 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, private schools, libraries, county agencies, and
 city utilities, to name a few.
 The administration of the US Domain was managed solely by the Domain
 Registrar in the past.  However, due to the increase of hosts,
 administration of subdomains is being delegated to others.
 Any computer in the United States may be registered in the US Domain.


 The US Domain hierarchy is based on political geography.  The
 namespace under .US is the state namespace, then the city namespace,
 then organization or computer name and so on.
 For example:
 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.

Cooper & Postel [Page 4] RFC 1386 The US Domain December 1992

 The use of un-registered names is not effective and causes problems
 for other users.  Inventing your own name and using it without
 registering is not a good idea.
 2.1  State Codes
 The state codes are the two letter US Postal abbreviations.
 2.2  City Codes or Locality Names
 Cities may be named (designated) by their full name (spelled out with
 hyphens replacing spaces (e.g., Los-Angeles or New-York)), or by a
 city code.  The first choice is the full city name, the second choice
 is the city codes from Western Union's "City Mnemonics" list, and a
 third choice is a code for your city chosen by the applicant.
 However, it is very desirable that all users in the same city use the
 same designator for the city.
 Abbreviated city names are a good idea, particularly when the city
 name is long, as there is much to type already.  One of the problems
 is that the city codes in the Western Union City Mnemonics list are
 sometimes not very good abbreviations.  Users sometimes tend to
 prefer abbreviations that are commonly used already from that region.
 Such as SF for San Francisco, MPK for Menlo Park.
 Exceptions have been made in the abbreviations, even though this
 causes extra work to keep track of these abbreviations.  One
 abbreviation for one city.  Applicants are told what codes are
 currently in use, however, if a city code is not used yet, and they
 would prefer to use a different code that is more common among the
 natives, then the new code is allowed.  However, once it's
 registered, then everyone else who registers in that city will have
 to use that code or spell out the full city name.
 Some applicants have tried to get a copy of the Western Union City
 Mnemonics code list but it is no longer available from Western Union.
 However, we do have a copy but it is not online. If you are
 requesting an abbreviated city code please let us know and we will
 gladly look it up for you.
 2.3  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

Cooper & Postel [Page 5] RFC 1386 The US Domain December 1992

 For large entities like large corporations with multiple facilities
 in several cities or states this often seems like a 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.
       For 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
 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
 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

Cooper & Postel [Page 6] RFC 1386 The US Domain December 1992

 Police.CITY.Culver-City.CA.US       <====  a city department
 Fire-Dept.CITY.Los-Angeles.CA.US    <====  a city department
 Fire-Dept.COUNTY.Los-Angeles.CA.US  <====  a county department
 SCAQMD.DISTRICT.CA.US                     <====  a regional district
 Bunker-Hill-Improvement.DISTRICT.LA.CA.US <====  a local district
 Huntington.LIB.LA.US                    <====  a private library
 Venice.LA-City.LIB.CA.US                <====  a city library
 MDR.LA-County.LIB.CA.US                 <====  a county library
 Los-Angeles.UC.STATE.CA.US      <====  UCLA
 Berkeley.UC.STATE.CA.US         <====  "CAL"
 Irvine.UC.STATE.CA.US           <====  University of Calif. Irvine
 Santa-Cruz.UC.STATE.CA.US       <====  University of Calif. Santa Cruz
 Northridge.CSU.STATE.CA.US      <====  Calif. State. Univ. Northridge
 Fullerton.CSU.STATE.CA.US       <====  Calif. State. Univ. Fullerton
 Sonoma.CSU.STATE.CA.US          <====  Calif. State. Univ. Sonoma
 SMCC.Santa-Monica.CC.CA.US      <====  a public community college
 Trade-Tech.Los-Angeles.CC.CA.US <====  a public community college
 Hamilton.High.LA-Unified.K12.CA.US      <====   a public K12 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
 St-Monica.High.Santa-Monica.CA.US       <====  a private high school
 St-Monica.Elem.Santa-Monica.CA.US       <====  a private elem. school
 Crossroads-School.Santa-Monica.CA.US    <====  a private school
 Mary-Ellens.Montessori-School.LA.CA.US  <====  a private school
 Leland-Stanford-Jr-Univ.Stanford.CA.US  <====  a private school
 Loyola-Marymount-Univ.Los-Angeles.CA.US <====  a private school

Cooper & Postel [Page 7] RFC 1386 The US Domain December 1992

 When appropriate, subdomains are delegated and partioned in various
 categories, such as:
                 K12.<state>.US   =   kindegarten thru 12th grade
                  CC.<state>.US   =   community colleges
                 LIB.<state>.US   =   libraries
               STATE.<state>.US   =   state government agencies
              <org-name>.FED.US   =   federal government agencies
 The Appendix-I contains the current US Domain Names BNF, but in
 actuality, the names under these subdomains may vary according to the
 decision of the administrators of these subdomains.
 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 host name.  Cities and in some cases counties are used.


 3.1  Requirements
 Anyone requesting to register a host in the US Domain is sent a copy
 of the US Domain policy and procedure, and must fill out a US Domain
 The US Domain template, is similar to the NIC Domain template
 however, it is not the same.  To request a copy of the US Domain
 questionnaire, send a message to the US Domain registrar (us-
    Note:  If you are registering a name in a delegated zone
           (see Section 3.3.6).  Please register with the
           contact for that zone.
 The key people must have electronic mailboxes (that work).  Please
 provide all the information indicated in the "Administrator" and
 "Technical Contact" slot.  This person 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 e-mail address. This is necessary in case something goes

Cooper & Postel [Page 8] RFC 1386 The US Domain December 1992

 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! or
 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, turn around time for registering a host is
 usually a day or two.  The nameservers are updated anywhere from 12
 to 24 hours later.
 There are two ways to be registered in the US Domain, directly, or by
 3.2  Direct Entries
 Direct entry in the database of the US Domain appeals most to
 individuals and small companies.  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.
 3.2.1 UUCP 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
 ok.  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 (, PSI (postmaster@UU2.PSI.COM)
 and CERFNET (  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 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:
 and request one.  See Appendix-II.

Cooper & Postel [Page 9] RFC 1386 The US Domain December 1992

 This 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]
   #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.
         For example:
 3.2.2 NON-IP Hosts
 To use US Domain names for non-IP hosts, there must be a forwarder
 host that is an IP host.  There must be an adminstrative 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

Cooper & Postel [Page 10] RFC 1386 The US Domain December 1992

        "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 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     |
 +----------+            +---------+            |                 |
     |                                          +-----------------+
 |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
 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

Cooper & Postel [Page 11] RFC 1386 The US Domain December 1992

 3.3  Delegated Subdomains
 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.
 Delegation of cities, companies within cities, schools (K12),
 community colleges (CC), libraries (LIB), state government (STATE),
 and federal government agencies, departments, etc., is acceptable and
 For a delegated portion of the namespace, 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 ok.
 Delegation of the whole State namespace is not yet implemented.  The
 delegated part of the name space is in the form of:
 3.3.1  Schools
 As schools begin to join the Internet, there ought to be a consistent
 scheme for naming them.  A "K12" name branch has been established in
 each state in the US Domain for this purpose.
 Public schools are usually organized by districts which can be larger
 or smaller than a city or county.

Cooper & Postel [Page 12] RFC 1386 The US Domain December 1992

 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.
 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 when they are needed, if the school's name is
 unique without such keywords don't use them.
 Typical K12 school names currently used are like:
 These names could be long.  Given the large number of schools,
 organizing by school district and state seems appropriate.  When
 there are many things to name some of the names must be long.
 In some cases there may be appropriate abbreviations that can be
 used.  For example Hamilton High School in Los Angeles could be:
    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
    Northridge.CSU.STATE.CA.US                <== a state university
 If a school has a bunch 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:

Cooper & Postel [Page 13] RFC 1386 The US Domain December 1992

 3.2.2  State Agencies
 US Domain namespace has been delegated to the state goverment
 agencies.  For example, in the State of Minnesota, the subdomain is
 This means that the person running the namservers for are
 responsible for naming agencies, of the state govermnent.  For
    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
 3.3.3  Federal Agencies
 A federal namespace has been delegated to 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
 3.3.4  Delegation Requirements
 When a subdomain is delegated, the following requirements must be
    1)  There must be a knowledgeable and competent technical contact,
        familiar with the Internet Domain Name System.  This
        requirement is easily satisified if the technical contact
        already runs some other nameservers.
    2)  Organizations requesting delegations must provide at least two
        independent (robust and reliable) DNS name servers in
        physically separate locations on the Internet.

Cooper & Postel [Page 14] RFC 1386 The US Domain December 1992

    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).
 3.3.5  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.
    2)  Note: In the past there was the concept of a "coordinator" for
        a group or a club or "Domain Park". They would arrange to
        coordinate the registration of all the computers used by
        members of the club and forward all the information for the
        group to the US Domain Administrator.  Most coordinators have
        moved into the position of administrator of that now delegated
    3)  Add the new technical contact to the "us-dom-adm" mailing list
        for distributing updates to the US Domain policies and
        procedures, or other pertinent information.
    4)  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.

Cooper & Postel [Page 15] RFC 1386 The US Domain December 1992

    5)  Send them a copy of the zone file so their initial zone file
        is identical to ours. For example:
   86400   SOA (
                                  920904  ;serial
                                  28800   ;refresh
                                  14400   ;retry
                                  3600000 ;expire
                                  86400 ) ;minim
      86400   NS
   50400   A
      86400   NS
     50400   A
      86400   HINFO   Sun 3/60 SunOs
      86400   MX      10
      86400   HINFO   386 Clone DOS
      86400   MX      10
        86400   HINFO   UNIX PC UNIX
        86400   MX      10
      86400   HINFO   PC AT ENIX
      86400   MX      10
       86400   HINFO   386 Clone DOS
       86400   MX      10

Cooper & Postel [Page 16] RFC 1386 The US Domain December 1992

    6)  The US Domain zone file must have the following records,
        showing the name, address, e-mail, and phone number of the
        technical contact for the delegated subdomain and the name of
        the delegated name space and the names of the nameservers.
          ;Delegated zone:
          ;Contact:  Steven Goodman
          ;          Marquette University
          ;          (414) 288-6734
      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.
    7)  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.
    8)  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.

Cooper & Postel [Page 17] RFC 1386 The US Domain December 1992

 3.3.6   Subdomain Contacts
 Approximately 680 individual hosts are registered, but we have
 delegated the following portions of the namespace.  We do not know
 how many hosts are registered under each of these subsdomains.
         DELEGATED ZONE             CONTACT
         ==============             =======
         BOULDER.CO.US              trent@XOR.COM
         COLOSPGS.CO.US             trent@XOR.COM
         DENVER.CO.US               trent@XOR.COM
         DVR.CO.US                  trent@XOR.COM
         PGH.PA.US                  ecd@CERT.ORG
         K12.CA.US                  mdm@NIC.CSU.NET
         CC.CA.US                   mdm@NIC.CSU.NET

Cooper & Postel [Page 18] RFC 1386 The US Domain December 1992

      The following MD.US counties have been delegated to
         AL.MD.US.       Allegany
         AA.MD.US.       Anne Arundel
         BA.MD.US.       Baltimore
         CAL.MD.US.      Calvert
         CAR.MD.US.      Caroline
         CE.MD.US.       Cecil
         CH.MD.US.       Charles
         DO.MD.US.       Dorchester
         FR.MD.US.       Frederick
         GA.MD.US.       Garrett
         HA.MD.US.       Harford
         HO.MD.US.       Howard
         KE.MD.US.       Kent
         MO.MD.US.       Montgomery
         PG.MD.US.       Prince George"s
         QA.MD.US.       Queen Anne's
         SM.MD.US.       St. Mary's
         SO.MD.US.       Somerset
         TA.MD.US.       Talbot
         WA.MD.US.       Washington
         WI.MD.US.       Wicomico
         WO.MD.US.       Worcester


 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.

Cooper & Postel [Page 19] RFC 1386 The US Domain December 1992

 The US Domain is currently supported by six name servers.
 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).
      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
 namservers 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

Cooper & Postel [Page 20] RFC 1386 The US Domain December 1992

 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
 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.

Cooper & Postel [Page 21] RFC 1386 The US Domain December 1992

 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:          A
            (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
 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:     CNAME
          (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.
 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, is the mail gateway that
 knows how to deliver mail to, but other machines on the
 network cannot deliver mail directly to  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

Cooper & Postel [Page 22] RFC 1386 The US Domain December 1992

 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.       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 RFC 1340.  The hardware type is
 called the Machine Name, and the software type is called the System
 The information users supply about this is often inconsistent or
 incomplete.  Please follow the terms in the current "Assigned
 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.     PTR
           (special name)                  (real name)
 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

Cooper & Postel [Page 23] RFC 1386 The US Domain December 1992

 following RRs might be entered into the .US zone.    MX      10       ELROY.JPL.NASA.GOV
       *    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.


 [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.

Cooper & Postel [Page 24] RFC 1386 The US Domain December 1992


 Security issues are not discussed in this memo.


 Ann Cooper
 USC/Information Sciences Institute
 4676 Admiralty Way
 Marina del Rey, CA  90292
 Phone:  1-310-822-1511
 Jon Postel
 USC/Information Sciences Institute
 4676 Admiralty Way
 Marina del Rey, CA  90292
 Phone:  1-310-822-1511

Cooper & Postel [Page 25] RFC 1386 The US Domain December 1992

                   APPENDIX-I:  US DOMAIN NAMES BNF
 <us-domain-name>    ::= <us-name><dot><us>
 <us-name>           ::= <state-name><dot><state-code> |
 <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> |
 <fed-name>          ::= <the dotted hierarchical name of a US
                          federal government agency>
 <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> |
 <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
 <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>

Cooper & Postel [Page 26] RFC 1386 The US Domain December 1992

 <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> ::= "CITY"
 <county> ::= "COUNTY" | "TOWNSHIP" | "PARISH"
 <dot> ::= "."
 <fed> ::= "FED"
 <agency> ::= "AGENCY" | "DISTRICT" | "K12" | "CC" | "LIB"
 <state> ::= "STATE" | "COMMONWEALTH"
 <us> ::= "US"
 Note:  "K12" may be used for public school districts, only.
        and "CC" may be used only for public community colleges,
        and "LIB" can only be used by libraries.

Cooper & Postel [Page 27] RFC 1386 The US Domain December 1992


To register a host in the US domain, the following information must be sent to the US Domain Registrar (Us-Domain@ISI.EDU). Questions may be sent by electronic mail to the above address, or by phone to Ann Cooper (310-822-1511).

(1) The name of the top-level domain to join.

         For example:  US

(2) The name of the administrative head of the organization, including

   title, mailing address, phone number, organization, and network
   mailbox.  This is the contact point for administrative and policy
   questions about the domain.  In the case of a research project,
   this should be the principal investigator.
         For example:
               Organization  The NetWorthy Corporation
               Name          Penelope Q. Sassafrass
               Title         President
               Mail Address  The NetWorthy Corporation
                             4676 Andrews Way, Suite 100
                             Santa Clara, CA 94302-1212
               Phone Number  (415) 123-4567
               Net Mailbox   Sassafrass@ECHO.TNC.COM

Cooper & Postel [Page 28] RFC 1386 The US Domain December 1992

(3) The name of the technical contact for the entry, including title,

   mailing address, phone number, organization, and network mailbox.
   This is the contact point for problems concerning the domain or
   zone, as well as for updating information about the domain or zone.
         For example:
            Technical Contact
               Organization  The NetWorthy Corporation
               Name          Ansel A. Aardvark
               Title         Executive Director
               Mail Address  The NetWorthy Corporation
                             4676 Andrews Way, Suite 100
                             Santa Clara, CA. 94302-1212
               Phone Number  (415) 123-6789
               Net Mailbox   Aardvark@ECHO.TNC.COM

(4) The name of the host. This is the name that will be used in tables

   and lists associating the domain with the domain server addresses.
   [While, from a technical standpoint, domain names can be quite long
   (programmers beware), shorter names are easier for people to cope
         For example:  NetWorthy.Santa-Clara.CA.US
         Or:  Alpha.NetWorthy.Santa-Clara.CA.US

(5) If this machine is not directly on the internet, how does it

   communicate with the Internet.  Through UUCP, CREN, etc?  Which
   forwarding host?
        For example:  The host "Networthy.Santa-Clara.CA.US" uses UUCP
        to connect to "RELAY.ISI.EDU" which is an Internet host.
        The administrator of RELAY.ISI.EDU must agree to be the
        forwarding host for Networthy.Santa-Clara.CA.US, and the
        forwarding host must know a delivery method and route to it.
        No double MXing.

Cooper & Postel [Page 29] RFC 1386 The US Domain December 1992

        If you are requesting an indirect connection, that is, a Mail
        Exchanger (MX) record, what is the name and mailbox of the
        administrator of the forwarding host.
        For example:John Smith

(6) Please describe your organization 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.

(7) What Domain Name System (DNS) Resource Records (RR) and values are

   to be entered.
   a.  A       Internet Address (internet hosts only)
   b.  HINFO   Host Information, Machine System
   c.  WKS     Well Known Services, Protocols, Ports (internet hosts only)
   d.  MX      Mail Exchanger (required for UUCP, and CREN hosts)
   An example of RRs for an internet host.
   NetWorthy.Santa-Clara.CA.US   IN   A
                            IN   HINFO   SUN-3/11OC UNIX
                            IN   MX      10  ISI.EDU
                            IN   WKS UDP (echo
                            IN   WKS TCP (telnet
   An example of RRs for a non-internet host.
   Beta.NetWorthy.Santa-Clara.CA.US   MX      10   RELAY.ISI.EDU
                                      HINFO   SUN-3/11OC UNIX

Cooper & Postel [Page 30] RFC 1386 The US Domain December 1992

(8) Where is the IN-ADDR pointer record to be entered. (For internet

   hosts only.)  It is your responsibility to see that this is done.
   Contact the administrator of the IP network your host is on.  The
   US Domain administration does not administer the network and cannot
   make these entries in the DNS database.
      For example:    PTR  NetWorthy.Santa-Clara.CA.US
   Who is the contact for the zone of the IN-ADDR.ARPA data, where
   this record will be entered?

(9) What Time to Live (TTL)? TTL is the time (in seconds) that a

   resolver will use the data it got from the domain server before it
   asks it again for the data.  A typical TTL is One Week 604800.
   (NOTE:  TTL is not applicable to non-Internet hosts.)
      For example:
         One Week   604800

Cooper & Postel [Page 31]

/data/webs/external/dokuwiki/data/pages/rfc/rfc1386.txt · Last modified: 1992/12/24 00:11 (external edit)