Child-to-Parent Synchronization in DNS
RFC 7477
Internet Engineering Task Force (IETF) W. Hardaker
Request for Comments: 7477 Parsons, Inc.
Category: Standards Track March 2015
ISSN: 2070-1721
Child-to-Parent Synchronization in DNS
Abstract
This document specifies how a child zone in the DNS can publish a
record to indicate to a parental agent that the parental agent may
copy and process certain records from the child zone. The existence
of the record and any change in its value can be monitored by a
parental agent and acted on depending on local policy.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc7477.
Copyright Notice
Copyright (c) 2015 IETF Trust and the persons identified as the
document authors. All rights reserved.
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Hardaker Standards Track [Page 1]
RFC 7477 Child-to-Parent Synchronization in DNS March 2015
Table of Contents
1. Introduction ....................................................2
1.1. Terminology Used in This Document ..........................3
2. Definition of the CSYNC RRType ..................................3
2.1. The CSYNC Resource Record Format ...........................4
2.1.1. The CSYNC Resource Record Wire Format ...............4
2.1.2. The CSYNC Presentation Format .......................6
2.1.3. CSYNC RR Example ....................................6
3. CSYNC Data Processing ...........................................6
3.1. Processing Procedure .......................................7
3.2. CSYNC Record Types .........................................8
3.2.1. The NS type .........................................8
3.2.2. The A and AAAA Types ................................9
4. Operational Considerations ......................................9
4.1. Error Reporting ...........................................10
4.2. Child Nameserver Selection ................................10
4.3. Out-of-Bailiwick NS Records ...............................10
4.4. Documented Parental Agent Type Support ....................11
4.5. Removal of the CSYNC Records ..............................11
4.6. Parent/Child/Grandchild Glue Synchronization ..............12
5. Security Considerations ........................................12
6. IANA Considerations ............................................12
7. References .....................................................13
7.1. Normative References ......................................13
7.2. Informative References ....................................14
Acknowledgments ...................................................15
Author's Address ..................................................15
1. Introduction
This document specifies how a child zone in the DNS ([RFC1034]
[RFC1035]) can publish a record to indicate to a parental agent (see
Section 1.1 for a definition of "parental agent") that it can copy
and process certain records from the child zone. The existence of
the record and any change in its value can be monitored by a parental
agent and acted on depending on local policy.
Currently, some resource records (RRs) in a parent zone are typically
expected to be in sync with the source data in the child's zone. The
most common records that should match are the nameserver (NS) records
and any necessary associated address records (A and AAAA), also known
as "glue records". These records are referred to as "delegation
records".
It has been challenging for operators of child DNS zones to update
their delegation records within the parent's set in a timely fashion.
These difficulties may stem from operator laziness as well as from
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