DNS Zone Transfer-over-TLS
draft-ietf-dprive-xfr-over-tls-02
dprive W. Toorop
Internet-Draft NLnet Labs
Updates: 1995, 7766 (if approved) S. Dickinson
Intended status: Standards Track Sinodun IT
Expires: January 14, 2021 S. Sahib
P. Aras
A. Mankin
Salesforce
July 13, 2020
DNS Zone Transfer-over-TLS
draft-ietf-dprive-xfr-over-tls-02
Abstract
DNS zone transfers are transmitted in clear text, which gives
attackers the opportunity to collect the content of a zone by
eavesdropping on network connections. The DNS Transaction Signature
(TSIG) mechanism is specified to restrict direct zone transfer to
authorized clients only, but it does not add confidentiality. This
document specifies use of TLS, rather then clear text, to prevent
zone contents collection via passive monitoring of zone transfers.
Status of This Memo
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provisions of BCP 78 and BCP 79.
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This Internet-Draft will expire on January 14, 2021.
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Copyright (c) 2020 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
Toorop, et al. Expires January 14, 2021 [Page 1]
Internet-Draft XFR-over-TLS July 2020
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Use Cases for XFR-over-TLS . . . . . . . . . . . . . . . . . 5
4. Connection and Data Flows in Existing XFR Mechanisms . . . . 5
4.1. AXFR Mechanism . . . . . . . . . . . . . . . . . . . . . 6
4.2. IXFR Mechanism . . . . . . . . . . . . . . . . . . . . . 7
4.3. Data Leakage of NOTIFY and SOA Message Exchanges . . . . 8
4.3.1. NOTIFY . . . . . . . . . . . . . . . . . . . . . . . 8
4.3.2. SOA . . . . . . . . . . . . . . . . . . . . . . . . . 8
5. Connections and Data Flows in XoT . . . . . . . . . . . . . . 8
5.1. TLS versions . . . . . . . . . . . . . . . . . . . . . . 8
5.2. Connection usage . . . . . . . . . . . . . . . . . . . . 8
5.2.1. High level XoT descriptions . . . . . . . . . . . . . 9
5.2.2. Previous specifications . . . . . . . . . . . . . . . 9
5.3. Update to RFC7766 . . . . . . . . . . . . . . . . . . . . 10
5.4. Connection Establishment . . . . . . . . . . . . . . . . 10
5.4.1. Draft Version Identification . . . . . . . . . . . . 11
5.5. Port selection . . . . . . . . . . . . . . . . . . . . . 11
5.6. AXoT mechanism . . . . . . . . . . . . . . . . . . . . . 11
5.6.1. Coverage and relationship to RFC5936 . . . . . . . . 12
5.6.2. AXoT connection and message handling . . . . . . . . 12
5.6.3. Padding AXoT responses . . . . . . . . . . . . . . . 14
5.7. IXoT mechanism . . . . . . . . . . . . . . . . . . . . . 15
5.7.1. Coverage and relationship to RFC1995 . . . . . . . . 15
5.7.2. IXoT connection and message handling . . . . . . . . 15
5.7.3. Condensation of responses . . . . . . . . . . . . . . 16
5.7.4. Fallback to AXFR . . . . . . . . . . . . . . . . . . 16
5.7.5. Padding of IXoT responses . . . . . . . . . . . . . . 16
6. Multi-primary Configurations . . . . . . . . . . . . . . . . 16
7. Zone Transfer with DoT - Authentication . . . . . . . . . . . 17
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