RFC 2916 (rfc2916) - Page 2 of 10

E

RFC 2916                  E.164 number and DNS            September 2000


   should contact the appropriate zone administrator in order to be
   listed, by examining the SOA resource record associated with the
   zone, just like in normal DNS operations.

   Of course, as with other domains, policies for such listings will be
   controlled on a subdomain basis and may differ in different parts of
   the world.

   To find the DNS names for a specific E.164 number, the following
   procedure is to be followed:

  1.  See that the E.164 number is written in its full form, including
      the countrycode IDDD.  Example: +46-8-9761234

  2.  Remove all non-digit characters with the exception of the leading
      '+'.  Example: +4689761234

  3.  Remove all characters with the exception of the digits.  Example:
      4689761234

  4.  Put dots (".") between each digit.  Example: 4.6.8.9.7.6.1.2.3.4

  5.  Reverse the order of the digits.  Example: 4.3.2.1.6.7.9.8.6.4

  6.  Append the string ".e164.arpa" to the end.  Example:
      4.3.2.1.6.7.9.8.6.4.e164.arpa

2.1 Special note about the '+'

   The '+' is kept in stage 2 in section 2 to flag that the number which
   the regular expression is operating on is a E.164 number.  Future
   work will be needed to determine how other numbering plans (such as
   closed ones) might be identified.  It is possible, but not definite,
   that they would use a similar mechanism as the one described in this
   document.

3. Fetching URIs given an E.164 number

   For a record in DNS, the NAPTR record is used for identifying
   available ways of contacting a specific node identified by that name.
   Specifically, it can be used for knowing what services exists for a
   specific domain name, including phone numbers by the use of the
   e164.arpa domain as described above.

   The identification is using the NAPTR resource record defined for use
   in the URN resolution process, but it can be generalized in a way
   that suits the needs specified in this document.




Faltstrom                   Standards Track