Selection and Operation of Secondary DNS Servers
RFC 2182
Document | Type |
RFC - Best Current Practice
(July 1997; Errata)
Also known as BCP 16
|
|
---|---|---|---|
Authors | Michael Patton , Scott Bradner , Robert Elz , Randy Bush | ||
Last updated | 2016-03-03 | ||
Stream | Internet Engineering Task Force (IETF) | ||
Formats | plain text html pdf htmlized (tools) htmlized bibtex | ||
Stream | WG state | (None) | |
Document shepherd | No shepherd assigned | ||
IESG | IESG state | RFC 2182 (Best Current Practice) | |
Consensus Boilerplate | Unknown | ||
Telechat date | |||
Responsible AD | (None) | ||
Send notices to | (None) |
Network Working Group R. Elz Request for Comments: 2182 University of Melbourne BCP: 16 R. Bush Category: Best Current Practice RGnet, Inc. S. Bradner Harvard University M. Patton Consultant July 1997 Selection and Operation of Secondary DNS Servers Status of this Memo This document specifies an Internet Best Current Practices for the Internet Community, and requests discussion and suggestions for improvements. Distribution of this memo is unlimited. Abstract The Domain Name System requires that multiple servers exist for every delegated domain (zone). This document discusses the selection of secondary servers for DNS zones. Both the physical and topological location of each server are material considerations when selecting secondary servers. The number of servers appropriate for a zone is also discussed, and some general secondary server maintenance issues considered. Elz, et al. Best Current Practice [Page 1] RFC 2182 Selection and Operation of Secondary DNS Servers July 1997 Contents Abstract ................................................... 1 1 Introduction ............................................... 2 2 Definitions ................................................ 2 3 Secondary Servers .......................................... 3 4 Unreachable servers ........................................ 5 5 How many secondaries? ...................................... 7 6 Finding Suitable Secondary Servers ......................... 8 7 Serial Number Maintenance .................................. 9 Security Considerations .................................... 11 References ................................................. 11 Acknowledgements ........................................... 11 Authors' Addresses ......................................... 11 1. Introduction A number of problems in DNS operations today are attributable to poor choices of secondary servers for DNS zones. The geographic placement as well as the diversity of network connectivity exhibited by the set of DNS servers for a zone can increase the reliability of that zone as well as improve overall network performance and access characteristics. Other considerations in server choice can unexpectedly lower reliability or impose extra demands on the network. This document discusses many of the issues that should be considered when selecting secondary servers for a zone. It offers guidance in how to best choose servers to serve a given zone. 2. Definitions For the purposes of this document, and only this document, the following definitions apply: DNS The Domain Name System [RFC1034, RFC1035]. Zone A part of the DNS tree, that is treated as a unit. Forward Zone A zone containing data mapping names to host addresses, mail exchange targets, etc. Elz, et al. Best Current Practice [Page 2] RFC 2182 Selection and Operation of Secondary DNS Servers July 1997 Reverse Zone A zone containing data used to map addresses to names. Server An implementation of the DNS protocols able to provide answers to queries. Answers may be from information known by the server, or information obtained from another server. Authoritative Server A server that knows the content of a DNS zone from local knowledge, and thus can answer queries about that zone without needing to query other servers. Listed Server An Authoritative Server for which there is an "NS" resource record (RR) in the zone. Primary Server An authoritative server for which the zone information is locally configured. Sometimes known as a Master server. Secondary Server An authoritative server that obtains information about a zone from a Primary Server via a zone transfer mechanism. Sometimes known as a Slave Server. Stealth Server An authoritative server, usually secondary,Show full document text