Protocol Modifications for the DNS Security Extensions
RFC 4035
Network Working Group R. Arends
Request for Comments: 4035 Telematica Instituut
Obsoletes: 2535, 3008, 3090, 3445, 3655, 3658, R. Austein
3755, 3757, 3845 ISC
Updates: 1034, 1035, 2136, 2181, 2308, 3225, M. Larson
3007, 3597, 3226 VeriSign
Category: Standards Track D. Massey
Colorado State University
S. Rose
NIST
March 2005
Protocol Modifications for the DNS Security Extensions
Status of This Memo
This document specifies an Internet standards track protocol for the
Internet community, and requests discussion and suggestions for
improvements. Please refer to the current edition of the "Internet
Official Protocol Standards" (STD 1) for the standardization state
and status of this protocol. Distribution of this memo is unlimited.
Copyright Notice
Copyright (C) The Internet Society (2005).
Abstract
This document is part of a family of documents that describe the DNS
Security Extensions (DNSSEC). The DNS Security Extensions are a
collection of new resource records and protocol modifications that
add data origin authentication and data integrity to the DNS. This
document describes the DNSSEC protocol modifications. This document
defines the concept of a signed zone, along with the requirements for
serving and resolving by using DNSSEC. These techniques allow a
security-aware resolver to authenticate both DNS resource records and
authoritative DNS error indications.
This document obsoletes RFC 2535 and incorporates changes from all
updates to RFC 2535.
Arends, et al. Standards Track [Page 1]
RFC 4035 DNSSEC Protocol Modifications March 2005
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
1.1. Background and Related Documents . . . . . . . . . . . . 4
1.2. Reserved Words . . . . . . . . . . . . . . . . . . . . . 4
2. Zone Signing . . . . . . . . . . . . . . . . . . . . . . . . . 4
2.1. Including DNSKEY RRs in a Zone . . . . . . . . . . . . . 5
2.2. Including RRSIG RRs in a Zone . . . . . . . . . . . . . 5
2.3. Including NSEC RRs in a Zone . . . . . . . . . . . . . . 6
2.4. Including DS RRs in a Zone . . . . . . . . . . . . . . . 7
2.5. Changes to the CNAME Resource Record. . . . . . . . . . 7
2.6. DNSSEC RR Types Appearing at Zone Cuts. . . . . . . . . 8
2.7. Example of a Secure Zone . . . . . . . . . . . . . . . . 8
3. Serving . . . . . . . . . . . . . . . . . . . . . . . . . . . 8
3.1. Authoritative Name Servers . . . . . . . . . . . . . . . 9
3.1.1. Including RRSIG RRs in a Response . . . . . . . 10
3.1.2. Including DNSKEY RRs in a Response . . . . . . . 11
3.1.3. Including NSEC RRs in a Response . . . . . . . . 11
3.1.4. Including DS RRs in a Response . . . . . . . . . 14
3.1.5. Responding to Queries for Type AXFR or IXFR . . 15
3.1.6. The AD and CD Bits in an Authoritative Response. 16
3.2. Recursive Name Servers . . . . . . . . . . . . . . . . . 17
3.2.1. The DO Bit . . . . . . . . . . . . . . . . . . . 17
3.2.2. The CD Bit . . . . . . . . . . . . . . . . . . . 17
3.2.3. The AD Bit . . . . . . . . . . . . . . . . . . . 18
3.3. Example DNSSEC Responses . . . . . . . . . . . . . . . . 19
4. Resolving . . . . . . . . . . . . . . . . . . . . . . . . . . 19
4.1. EDNS Support . . . . . . . . . . . . . . . . . . . . . . 19
4.2. Signature Verification Support . . . . . . . . . . . . . 19
4.3. Determining Security Status of Data . . . . . . . . . . 20
4.4. Configured Trust Anchors . . . . . . . . . . . . . . . . 21
4.5. Response Caching . . . . . . . . . . . . . . . . . . . . 21
4.6. Handling of the CD and AD Bits . . . . . . . . . . . . . 22
4.7. Caching BAD Data . . . . . . . . . . . . . . . . . . . . 22
4.8. Synthesized CNAMEs . . . . . . . . . . . . . . . . . . . 23
4.9. Stub Resolvers . . . . . . . . . . . . . . . . . . . . . 23
4.9.1. Handling of the DO Bit . . . . . . . . . . . . . 24
4.9.2. Handling of the CD Bit . . . . . . . . . . . . . 24
4.9.3. Handling of the AD Bit . . . . . . . . . . . . . 24
5. Authenticating DNS Responses . . . . . . . . . . . . . . . . . 25
5.1. Special Considerations for Islands of Security . . . . . 26
Show full document text