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