::= <let-dig-hyp> | <let-dig-hyp> 

      <let-dig-hyp> ::=  | "-"

       ::=  | 

       ::= any one of the 52 alphabetic characters A through Z
      in upper case and a through z in lower case

       ::= any one of the ten digits 0 through 9

   Note that while upper and lower case letters are allowed in domain
   names no significance is attached to the case.  That is, two names
   with the same spelling but different case are to be treated as if
   identical.

   The labels must follow the rules for ARPANET host names.  They must
   start with a letter, end with a letter or digit, and have as interior
   characters only letters, digits, and hyphen.  There are also some
   restrictions on the length.  Labels must be 63 characters or less.

   For example, the following strings identify hosts in the ARPA
   Internet:

      F.ISI.ARPA     LINKABIT-DCN5.ARPA     UCL-TAC.ARPA













 

RFC 882                                                    November 1983
                                  Domain Names - Concepts and Facilities


REFERENCES and BIBLIOGRAPHY

   [1]  E. Feinler, K. Harrenstien, Z. Su, and V. White, "DOD Internet
        Host Table Specification", RFC 810, Network Information Center,
        SRI International, March 1982.

   [2]  J. Postel, "Computer Mail Meeting Notes", RFC 805,
        USC/Information Sciences Institute, February 1982.

   [3]  Z. Su, and J. Postel, "The Domain Naming Convention for Internet
        User Applications", RFC 819, Network Information Center, SRI
        International, August 1982.

   [4]  Z. Su, "A Distributed System for Internet Name Service",
        RFC 830, Network Information Center, SRI International,
        October 1982.

   [5]  K. Harrenstien, and V. White, "NICNAME/WHOIS", RFC 812, Network
        Information Center, SRI International, March 1982.

   [6]  M. Solomon, L. Landweber, and D. Neuhengen, "The CSNET Name
        Server", Computer Networks, vol 6, nr 3, July 1982.

   [7]  K. Harrenstien, "NAME/FINGER", RFC 742, Network Information
        Center, SRI International, December 1977.

   [8]  J. Postel, "Internet Name Server", IEN 116, USC/Information
        Sciences Institute, August 1979.

   [9]  K. Harrenstien, V. White, and E. Feinler, "Hostnames Server",
        RFC 811, Network Information Center, SRI International,
        March 1982.

   [10] J. Postel, "Transmission Control Protocol", RFC 793,
        USC/Information Sciences Institute, September 1981.

   [11] J. Postel, "User Datagram Protocol", RFC 768, USC/Information
        Sciences Institute, August 1980.

   [12] J. Postel, "Simple Mail Transfer Protocol", RFC 821,
        USC/Information Sciences Institute, August 1980.

   [13] J. Reynolds, and J. Postel, "Assigned Numbers", RFC 870,
        USC/Information Sciences Institute, October 1983.

   [14] P. Mockapetris, "Domain Names - Implementation and
        Specification", RFC 883, USC/Information Sciences Institute,
        November 1983.