Wrapped Encapsulating Security Payload (ESP) for Traffic Visibility
RFC 5840
Internet Engineering Task Force (IETF) K. Grewal
Request for Comments: 5840 Intel Corporation
Category: Standards Track G. Montenegro
ISSN: 2070-1721 Microsoft Corporation
M. Bhatia
Alcatel-Lucent
April 2010
Wrapped Encapsulating Security Payload (ESP) for Traffic Visibility
Abstract
This document describes the Wrapped Encapsulating Security Payload
(WESP) protocol, which builds on the Encapsulating Security Payload
(ESP) RFC 4303 and is designed to allow intermediate devices to (1)
ascertain if data confidentiality is being employed within ESP, and
if not, (2) inspect the IPsec packets for network monitoring and
access control functions. Currently, in the IPsec ESP standard,
there is no deterministic way to differentiate between encrypted and
unencrypted payloads by simply examining a packet. This poses
certain challenges to the intermediate devices that need to deep
inspect the packet before making a decision on what should be done
with that packet (Inspect and/or Allow/Drop). The mechanism
described in this document can be used to easily disambiguate
integrity-only ESP from ESP-encrypted packets, without compromising
on the security provided by ESP.
Status of This Memo
This is an Internet Standards Track document.
This document is a product of the Internet Engineering Task Force
(IETF). It represents the consensus of the IETF community. It has
received public review and has been approved for publication by the
Internet Engineering Steering Group (IESG). Further information on
Internet Standards is available in Section 2 of RFC 5741.
Information about the current status of this document, any errata,
and how to provide feedback on it may be obtained at
http://www.rfc-editor.org/info/rfc5840.
Grewal, et al. Standards Track [Page 1]
RFC 5840 WESP for Traffic Visibility April 2010
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Table of Contents
1. Introduction ....................................................3
1.1. Requirements Language ......................................4
1.2. Applicability Statement ....................................4
2. Wrapped ESP (WESP) Header Format ................................5
2.1. UDP Encapsulation ..........................................8
2.2. Transport and Tunnel Mode Considerations ...................9
2.2.1. Transport Mode Processing ...........................9
2.2.2. Tunnel Mode Processing .............................10
2.3. IKE Considerations ........................................11
3. Security Considerations ........................................12
4. IANA Considerations ............................................13
5. Acknowledgments ................................................13
6. References .....................................................14
6.1. Normative References ......................................14
6.2. Informative References ....................................14
Grewal, et al. Standards Track [Page 2]
RFC 5840 WESP for Traffic Visibility April 2010
1. Introduction
Use of ESP within IPsec [RFC4303] specifies how ESP packet
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