Contents

Introduction

Overview

Introduction

This document describes common Domain Name System (DNS) response codes (RCodes) in DNS query logs.

Overview

This table details the function of the most common DNS return messages and corresponding (RCodes) that may appear in your logs while doing a DNS query. Each RCode has its own purpose in the DNS infrastructure. Typically, you see NOERROR (RCODE:0) when doing most of your successful browsing. All of the other return codes are considered errors.

For an exhaustive list of these codes, please see the DNS RCODEs section of this link: Domain Name System (DNS) Parameters

DNS Return Message

DNS Response Code

Function

NOERROR

RCODE:0

DNS Query completed successfully

FORMERR

RCODE:1

DNS Query Format Error

SERVFAIL

RCODE:2

Server failed to complete the DNS request

NXDOMAIN

RCODE:3

Domain name does not exist

NOTIMP

RCODE:4

Function not implemented

REFUSED

RCODE:5

The server refused to answer for the query

YXDOMAIN

RCODE:6

Name that can not exist, does exist

XRRSET

RCODE:7

RRset that can not exist, does exist

NOTAUTH

RCODE:8

Server not authoritative for the zone

NOTZONE

RCODE:9

Name not in zone