RFC 973 (rfc973) - Page 1 of 10


Domain system changes and observations



Alternative Format: Original Text Document



Network Working Group                                   Paul Mockapetris
Request for Comments: 973                                            ISI
                                                            January 1986

                 Domain System Changes and Observations


STATUS OF THIS MEMO

   This RFC documents updates to Domain Name System specifications
   RFC-882 [1] and RFC-883 [2], suggests some operational guidelines,
   and discusses some experiences and problem areas in the present
   system.  Distribution of this memo is unlimited.

   This document includes all changes to the Domain System through
   January, 1986.  Change notices and additional discussion are
   available online in file [USC-ISIB.ARPA]DOMAIN.CHANGES.

OVERVIEW

   This memo is divided into four major sections:

      "UPDATES" which discusses changes to the domain specification
      which are in widespread use and should be regarded as being part
      of the specification.

      "OPERATION GUIDELINES" which suggests rules-of-thumb for using the
      domain system and configuring your database which are appropriate
      in most cases, but which may have rare exceptions.

      "EXPERIENCES" which discusses some unusual situations and common
      bugs which are encountered in the present system, and should be
      helpful in problem determination and tuning.

      "PROBLEM AREAS" which discusses some shortcomings in the present
      system which may be addressed in future versions.

UPDATES

   This section discusses changes to the specification which are final,
   and should be incorporated in all domain system software.

   TTL timeouts too small

      The 16 bit TTL field in RRs could not represent a large enough
      time interval.  The 16 bit field, using seconds for units, has a
      maximum period of approximately 18 hours.

      All time values, including all TTLs and the MINIMUM field of the
      SOA RR, are expanded to 32 bits.



Mockapetris