IETF 76 - Tutorials

Hiroshima, Japan
November 8-13, 2009

DNS for Programmers

Presented by: Peter Koch & Olafur Gudmundsson

Sunday, November 8, 2009 - 13:00-14:50

Room: Acacia 2

Olafur Gudmundsson <>

(DNSEXT chair)

Peter Koch <>
(DNSOP co-chair)

The Domain Name System (DNS) is one of the corner stones of the Internet. Without the DNS, wide use of the network would not be easily possible. Various IETF working groups' protocols/applications have needs for universal distribution of information related to their operation. Therefore the DNS -- the only universal lookup service -- is the natural fit to carry certain information.

While the DNS is indeed a very valuable and powerful tool and it has been fulfilling its tasks quite well for almost two decades now, it cannot serve all proposed new uses equally well. And even if the DNS is the lookup system of choice, the extent to which the DNS is used still needs to be considered. After all, the DNS's strength, its global availability, turns out to be a weakness when it comes down to protocol corner cases, operational issues and some not immediately obvious properties.

This tutorial will cover DNS basics and how best to take advantage of DNS in other, higher level protocols.

We will cover in particular frequently discussed topics and rumors as well as design criteria to be used. Among the topics here are (in no particular order):

  • New RR types & Unknown RR type support
  • DNS tree properties and non-properties
  • Additional-section processing rules
  • Wildcards
  • ...

Participants in this tutorial will gain an understanding of the DNS, its principles and operation. Given the time constraints and the special IETF focus, the tutorial will not cover DNS server or resolver configuration, server operations or how to further develop or optimize the DNS protocol intrinsics. Fortunately, experiences with these aren't expected, either.

This is a cross-area effort, so most welcome to attend are people designing protocols in, e.g., the Applications and RAI areas (wg chairs, document editors, design team members, other interested parties). We will also address "early document review".