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Common DNS Operational and Configuration Errors (RFC1912)

IP.com Disclosure Number: IPCOM000004156D
Original Publication Date: 1996-Feb-01
Included in the Prior Art Database: 2000-Sep-13
Document File: 13 page(s) / 36K

Publishing Venue

Internet Society Requests For Comment (RFCs)

Related People

D. Barr: AUTHOR

Abstract

This memo describes errors often found in both the operation of Domain Name System (DNS) servers, and in the data that these DNS servers contain. This memo tries to summarize current Internet requirements as well as common practice in the operation and configuration of the DNS. This memo also tries to summarize or expand upon issues raised in [RFC 1537].

This text was extracted from a ASCII document.
This is the abbreviated version, containing approximately 8% of the total text.

Network Working Group D. Barr

Request for Comments: 1912 The Pennsylvania State University

Obsoletes: 1537 February 1996

Category: Informational

Common DNS Operational and Configuration Errors

Status of this Memo

This memo provides information for the Internet community. This memo

does not specify an Internet standard of any kind. Distribution of

this memo is unlimited.

Abstract

This memo describes errors often found in both the operation of

Domain Name System (DNS) servers, and in the data that these DNS

servers contain. This memo tries to summarize current Internet

requirements as well as common practice in the operation and

configuration of the DNS. This memo also tries to summarize or

expand upon issues raised in [RFC 1537].

1. Introduction

Running a nameserver is not a trivial task. There are many things

that can go wrong, and many decisions have to be made about what data

to put in the DNS and how to set up servers. This memo attempts to

address many of the common mistakes and pitfalls that are made in DNS

data as well as in the operation of nameservers. Discussions are

also made regarding some other relevant issues such as server or

resolver bugs, and a few political issues with respect to the

operation of DNS on the Internet.

2. DNS Data

This section discusses problems people typically have with the DNS

data in their nameserver, as found in the zone data files that the

nameserver loads into memory.

2.1 Inconsistent, Missing, or Bad Data

Every Internet-reachable host should have a name. The consequences

of this are becoming more and more obvious. Many services available

on the Internet will not talk to you if you aren't correctly

registered in the DNS.

Make sure your PTR and A records match. For every IP address, there

should be a matching PTR record in the in-addr.arpa domain. If a

host is multi-homed, (more than one IP address) make sure that all IP

addresses have a corresponding PTR record (not just the first one).

Failure to have matching PTR and A records can cause loss of Internet

services similar to not being registered in the DNS at all. Also,

PTR records must point back to a valid A record, not a alias defined

by a CNAME. It is highly recommended that you use some software

which automates this checking, or generate your DNS data from a

database which automatically creates consistent data.

DNS domain names consist of "labels" separated by single dots. The

DNS is very liberal in its rules for the allo...