draft-ietf-ipsecme-traffic-visibility-12.txt   rfc5840.txt 
Network Working Group K. Grewal
Internet Draft Intel Corporation
Intended status: Standards Track G. Montenegro
Expires: July 19, 2010 Microsoft Corporation
M. Bhatia
Alcatel-Lucent
January 20, 2010
Wrapped ESP for Traffic Visibility Internet Engineering Task Force (IETF) K. Grewal
draft-ietf-ipsecme-traffic-visibility-12.txt Request for Comments: 5840 Intel Corporation
Category: Standards Track G. Montenegro
ISSN: 2070-1721 Microsoft Corporation
M. Bhatia
Alcatel-Lucent
April 2010
Status of this Memo Wrapped Encapsulating Security Payload (ESP) for Traffic Visibility
This Internet-Draft is submitted to IETF in full conformance Abstract
with the provisions of BCP 78 and BCP 79. This document may
contain material from IETF Documents or IETF Contributions
published or made publicly available before November 10, 2008.
The person(s) controlling the copyright in some of this material
may not have granted the IETF Trust the right to allow
modifications of such material outside the IETF Standards
Process. Without obtaining an adequate license from the
person(s) controlling the copyright in such materials, this
document may not be modified outside the IETF Standards Process,
and derivative works of it may not be created outside the IETF
Standards Process, except to format it for publication as an RFC
or to translate it into languages other than English.
Internet-Drafts are working documents of the Internet This document describes the Wrapped Encapsulating Security Payload
Engineering Task Force (IETF), its areas, and its working (WESP) protocol, which builds on the Encapsulating Security Payload
groups. Note that other groups may also distribute working (ESP) RFC 4303 and is designed to allow intermediate devices to (1)
documents as Internet-Drafts. 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.
Internet-Drafts are draft documents valid for a maximum of six Status of This Memo
months and may be updated, replaced, or obsoleted by other
documents at any time. It is inappropriate to use Internet-
Drafts as reference material or to cite them other than as "work
in progress."
The list of current Internet-Drafts can be accessed at This is an Internet Standards Track document.
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at This document is a product of the Internet Engineering Task Force
http://www.ietf.org/shadow.html. (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.
This Internet-Draft will expire on July 19, 2010. 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.
Copyright Copyright Notice
Copyright (c) 2010 IETF Trust and the persons identified as the Copyright (c) 2010 IETF Trust and the persons identified as the
document authors. All rights reserved. document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents Provisions Relating to IETF Documents
(http://trustee.ietf.org/license-info) in effect on the date of (http://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with carefully, as they describe your rights and restrictions with respect
respect to this document. Code Components extracted from this to this document. Code Components extracted from this document must
document must include Simplified BSD License text as described include Simplified BSD License text as described in Section 4.e of
in Section 4.e of the Trust Legal Provisions and are provided the Trust Legal Provisions and are provided without warranty as
without warranty as described in the Simplified BSD License. described in the Simplified BSD License.
Abstract
This document describes the Wrapped Encapsulating Security This document may contain material from IETF Documents or IETF
Payload (WESP) protocol, which builds on the Encapsulating Contributions published or made publicly available before November
Security Payload (ESP) [RFC4303], and is designed to allow 10, 2008. The person(s) controlling the copyright in some of this
intermediate devices to (1) ascertain if data confidentiality is material may not have granted the IETF Trust the right to allow
being employed within ESP and if not, (2) inspect the IPsec modifications of such material outside the IETF Standards Process.
packets for network monitoring and access control functions. Without obtaining an adequate license from the person(s) controlling
Currently in the IPsec ESP standard, there is no deterministic the copyright in such materials, this document may not be modified
way to differentiate between encrypted and unencrypted payloads outside the IETF Standards Process, and derivative works of it may
by simply examining a packet. This poses certain challenges to not be created outside the IETF Standards Process, except to format
the intermediate devices that need to deep inspect the packet it for publication as an RFC or to translate it into languages other
before making a decision on what should be done with that packet than English.
(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.
Table of Contents Table of Contents
1. Introduction...................................................3 1. Introduction ....................................................3
1.1. Requirements Language.....................................4 1.1. Requirements Language ......................................4
1.2. Applicability Statement...................................4 1.2. Applicability Statement ....................................4
2. Wrapped ESP (WESP) Header format...............................5 2. Wrapped ESP (WESP) Header Format ................................5
2.1. UDP Encapsulation.........................................8 2.1. UDP Encapsulation ..........................................8
2.2. Transport and Tunnel Mode Considerations..................9 2.2. Transport and Tunnel Mode Considerations ...................9
2.2.1. Transport Mode Processing...........................10 2.2.1. Transport Mode Processing ...........................9
2.2.2. Tunnel Mode Processing..............................11 2.2.2. Tunnel Mode Processing .............................10
2.3. IKE Considerations.......................................12 2.3. IKE Considerations ........................................11
3. Security Considerations.......................................12 3. Security Considerations ........................................12
4. IANA Considerations...........................................13 4. IANA Considerations ............................................13
5. Acknowledgments...............................................13 5. Acknowledgments ................................................13
6. References....................................................14 6. References .....................................................14
6.1. Normative References.....................................14 6.1. Normative References ......................................14
6.2. Informative References...................................14 6.2. Informative References ....................................14
1. Introduction 1. Introduction
Use of ESP within IPsec [RFC4303] specifies how ESP packet Use of ESP within IPsec [RFC4303] specifies how ESP packet
encapsulation is performed. It also specifies that ESP can encapsulation is performed. It also specifies that ESP can provide
provide data confidentiality and data integrity services. Data data confidentiality and data integrity services. Data integrity
integrity without data confidentiality ("integrity-only ESP") is without data confidentiality ("integrity-only ESP") is possible via
possible via the ESP-NULL encryption algorithm [RFC2410] or via the ESP-NULL encryption algorithm [RFC2410] or via combined-mode
combined-mode algorithms such as AES-GMAC [RFC4543]. The exact algorithms such as AES-GMAC [RFC4543]. The exact encapsulation and
encapsulation and algorithms employed are negotiated out-of-band algorithms employed are negotiated out of band using, for example,
using, for example, IKEv2 [RFC4306] and based on policy. Internet Key Exchange Protocol version 2 (IKEv2) [RFC4306] and based
on policy.
Enterprise environments typically employ numerous security Enterprise environments typically employ numerous security policies
policies (and tools for enforcing them), as related to access (and tools for enforcing them), as related to access control, content
control, content screening, firewalls, network monitoring screening, firewalls, network monitoring functions, deep packet
functions, deep packet inspection, Intrusion Detection and inspection, Intrusion Detection and Prevention Systems (IDS and IPS),
Prevention Systems (IDS and IPS), scanning and detection of scanning and detection of viruses and worms, etc. In order to
viruses and worms, etc. In order to enforce these policies, enforce these policies, network tools and intermediate devices
network tools and intermediate devices require visibility into require visibility into packets, ranging from simple packet header
packets, ranging from simple packet header inspection to deeper inspection to deeper payload examination. Network security protocols
payload examination. Network security protocols which encrypt that encrypt the data in transit prevent these network tools from
the data in transit prevent these network tools from performing performing the aforementioned functions.
the aforementioned functions.
When employing IPsec within an enterprise environment, it is When employing IPsec within an enterprise environment, it is
desirable to employ ESP instead of AH [RFC4302], as AH does not desirable to employ ESP instead of Authentication Header (AH)
work in NAT environments. Furthermore, in order to preserve the [RFC4302], as AH does not work in NAT environments. Furthermore, in
above network monitoring functions, it is desirable to use order to preserve the above network monitoring functions, it is
integrity-only ESP. In a mixed-mode environment, some packets desirable to use integrity-only ESP. In a mixed-mode environment,
containing sensitive data employ a given encryption cipher some packets containing sensitive data employ a given encryption
suite, while other packets employ integrity-only ESP. For an cipher suite, while other packets employ integrity-only ESP. For an
intermediate device to unambiguously distinguish which packets intermediate device to unambiguously distinguish which packets are
are using integrity-only ESP requires knowledge of all the using integrity-only ESP requires knowledge of all the policies being
policies being employed for each protected session. This is employed for each protected session. This is clearly not practical.
clearly not practical. Heuristics-based methods can be employed Heuristics-based methods can be employed to parse the packets, but
to parse the packets, but these can be very expensive, requiring these can be very expensive, requiring numerous rules based on each
numerous rules based on each different protocol and payload. different protocol and payload. Even then, the parsing may not be
Even then, the parsing may not be robust in cases where fields robust in cases where fields within a given encrypted packet happen
within a given encrypted packet happen to resemble the fields to resemble the fields for a given protocol or heuristic rule. In
for a given protocol or heuristic rule. In cases where the cases where the packets may be encrypted, it is also wasteful to
packets may be encrypted, it is also wasteful to check against check against heuristics-based rules, when a simple exception policy
heuristics-based rules, when a simple exception policy (e.g., (e.g., allow, drop, or redirect) can be employed to handle the
allow, drop or redirect) can be employed to handle the encrypted encrypted packets. Because of the non-deterministic nature of
packets. Because of the non-deterministic nature of heuristics- heuristics-based rules for disambiguating between encrypted and non-
based rules for disambiguating between encrypted and non-
encrypted data, an alternative method for enabling intermediate encrypted data, an alternative method for enabling intermediate
devices to function in encrypted data environments needs to be devices to function in encrypted data environments needs to be
defined. Additionally there are many types and classes of defined. Additionally, there are many types and classes of network
network devices employed within a given network and a devices employed within a given network and a deterministic approach
deterministic approach provides a simple solution for all of provides a simple solution for all of them. Enterprise environments
them. Enterprise environments typically use both stateful and typically use both stateful and stateless packet inspection
stateless packet inspection mechanisms. The previous mechanisms. The previous considerations weigh particularly heavy on
considerations weigh particularly heavy on stateless mechanisms stateless mechanisms such as router Access Control Lists (ACLs) and
such as router ACLs and NetFlow exporters. Nevertheless, a NetFlow exporters. Nevertheless, a deterministic approach provides a
deterministic approach provides a simple solution for the myriad simple solution for the myriad types of devices employed within a
types of devices employed within a network, regardless of their network, regardless of their stateful or stateless nature.
stateful or stateless nature.
This document defines a mechanism to provide additional This document defines a mechanism to provide additional information
information in relevant IPsec packets so intermediate devices in relevant IPsec packets so intermediate devices can efficiently
can efficiently differentiate between encrypted and integrity- differentiate between encrypted and integrity-only packets.
only packets. Additionally and in the interest of consistency, Additionally, and in the interest of consistency, this extended
this extended format can also be used to carry encrypted packets format can also be used to carry encrypted packets without loss in
without loss in disambiguation. disambiguation.
The document is consistent with the operation of ESP in NAT This document is consistent with the operation of ESP in NAT
environments [RFC3947]. environments [RFC3947].
The design principles for this protocol are the following: The design principles for this protocol are the following:
o Allow easy identification and parsing of integrity-only IPsec o Allow easy identification and parsing of integrity-only IPsec
traffic traffic
o Leverage the existing hardware IPsec parsing engines as much o Leverage the existing hardware IPsec parsing engines as much as
as possible to minimize additional hardware design costs possible to minimize additional hardware design costs
o Minimize the packet overhead in the common case o Minimize the packet overhead in the common case
1.1. Requirements Language 1.1. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
NOT", "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
"OPTIONAL" in this document are to be interpreted as described document are to be interpreted as described in RFC 2119 [RFC2119].
in RFC 2119 [RFC2119].
1.2. Applicability Statement 1.2. Applicability Statement
The document is applicable only to the wrapped ESP header The document is applicable only to the wrapped ESP header defined
defined below, and does not describe any changes to either ESP below, and does not describe any changes to either ESP [RFC4303] or
[RFC4303] nor IP Authentication Header (AH) [RFC4302]. the IP Authentication Header (AH) [RFC4302].
There are two well accepted ways to enable intermediate security There are two well-accepted ways to enable intermediate security
devices to distinguish between encrypted and unencrypted ESP devices to distinguish between encrypted and unencrypted ESP traffic:
traffic:
- The heuristics approach [Heuristics I-D] has the intermediate - The heuristics approach [Heuristics] has the intermediate node
node inspect the unchanged ESP traffic, to determine with inspect the unchanged ESP traffic, to determine with extremely high
extremely high probability whether or not the traffic stream is probability whether or not the traffic stream is encrypted.
encrypted.
- The Wrapped ESP (WESP) approach described in this document, in - The Wrapped ESP (WESP) approach, described in this document, in
contrast, requires the ESP endpoints to be modified to support contrast, requires the ESP endpoints to be modified to support the
the new protocol. WESP allows the intermediate node to new protocol. WESP allows the intermediate node to distinguish
distinguish encrypted and unencrypted traffic deterministically, encrypted and unencrypted traffic deterministically, using a
using a simpler implementation for the intermediate node. simpler implementation for the intermediate node.
Both approaches are being documented simultaneously by the IP Both approaches are being documented simultaneously by the IP
Security Maintenance and Extensions (IPsecME) Working Group, Security Maintenance and Extensions (IPsecME) Working Group, with
with WESP being put on Standards Track while the heuristics WESP (this document) as a Standards Track RFC while the heuristics
approach is being published as an Informational RFC. While approach is expected to be published as an Informational RFC. While
endpoints are being modified to adopt WESP, we expect both endpoints are being modified to adopt WESP, we expect both approaches
approaches to coexist for years, because the heuristic approach to coexist for years because the heuristic approach is needed to
is needed to inspect traffic where at least one of the endpoints inspect traffic where at least one of the endpoints has not been
has not been modified. In other words, intermediate nodes are modified. In other words, intermediate nodes are expected to support
expected to support both approaches in order to achieve good both approaches in order to achieve good security and performance
security and performance during the transition period. during the transition period.
2. Wrapped ESP (WESP) Header format 2. Wrapped ESP (WESP) Header Format
Wrapped ESP encapsulation (WESP) uses protocol number (TBD via Wrapped ESP (WESP) encapsulation uses protocol number 141.
IANA). Accordingly, the (outer) protocol header (IPv4, IPv6, or Accordingly, the (outer) protocol header (IPv4, IPv6, or Extension)
Extension) that immediately precedes the WESP header SHALL that immediately precedes the WESP header SHALL contain the value
contain the value (TBD via IANA) in its Protocol (IPv4) or Next (141) in its Protocol (IPv4) or Next Header (IPv6, Extension) field.
Header (IPv6, Extension) field. WESP provides additional WESP provides additional attributes in each packet to assist in
attributes in each packet to assist in differentiating between differentiating between encrypted and non-encrypted data, and to aid
encrypted and non-encrypted data, and to aid parsing of the in parsing of the packet. WESP follows RFC 4303 for all IPv6 and
packet. WESP follows RFC 4303 for all IPv6 and IPv4 IPv4 considerations (e.g., alignment considerations).
considerations (e.g., alignment considerations).
This extension essentially acts as a wrapper to the existing ESP This extension essentially acts as a wrapper to the existing ESP
protocol and provides an additional 4 octets at the front of the protocol and provides an additional 4 octets at the front of the
existing ESP packet for IPv4. For IPv6, additional padding may existing ESP packet for IPv4. For IPv6, additional padding may be
be required and this is described below. required and this is described below.
The packet format may be depicted as follows: The packet format may be depicted as follows:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Wrapped ESP Header | | Wrapped ESP Header |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Existing ESP Encapsulation | | Existing ESP Encapsulation |
~ ~ ~ ~
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 1 WESP Packet Format Figure 1: WESP Packet Format
By preserving the body of the existing ESP packet format, a By preserving the body of the existing ESP packet format, a compliant
compliant implementation can simply add in the new header, implementation can simply add in the new header, without needing to
without needing to change the body of the packet. The value of change the body of the packet. The value of the new protocol used to
the new protocol used to identify this new header is TBD via identify this new header is 141. Further details are shown below:
IANA. Further details are shown below:
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | HdrLen | TrailerLen | Flags | | Next Header | HdrLen | TrailerLen | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Padding (optional) | | Padding (optional) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Existing ESP Encapsulation | | Existing ESP Encapsulation |
~ ~ ~ ~
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 2 Detailed WESP Packet Format Figure 2: Detailed WESP Packet Format
Where: Where:
Next Header, 8 bits: This field MUST be the same as the Next Next Header, 8 bits: This field MUST be the same as the Next Header
Header field in the ESP trailer when using ESP in the Integrity field in the ESP trailer when using ESP in the Integrity-only mode.
only mode. When using ESP with encryption, the "Next Header" When using ESP with encryption, the "Next Header" field looses this
field looses this name and semantics and becomes an empty field name and semantics and becomes an empty field that MUST be
which MUST be initialized to all zeros. The receiver MUST do initialized to all zeros. The receiver MUST do some sanity checks
some sanity checks before the WESP packet is accepted. The before the WESP packet is accepted. The receiver MUST ensure that
receiver MUST ensure that the Next Header field in the WESP the Next Header field in the WESP header and the Next Header field in
header and the Next Header field in the ESP trailer match when the ESP trailer match when using ESP in the Integrity-only mode. The
using ESP in the Integrity only mode. The packet MUST be dropped packet MUST be dropped if the two do not match. Similarly, the
if the two do not match. Similarly, the receiver MUST ensure receiver MUST ensure that the Next Header field in the WESP header is
that the Next Header field in the WESP header is an empty field an empty field initialized to zero if using WESP with encryption.
initialized to zero if using WESP with encryption. The WESP The WESP flags dictate if the packet is encrypted.
flags dictate if the packet is encrypted.
HdrLen, 8 bits: Offset from the beginning of the WESP header to HdrLen, 8 bits: Offset from the beginning of the WESP header to the
the beginning of the Rest of Payload Data (i.e., past the IV, if beginning of the Rest of Payload Data (i.e., past the IV, if present
present and any other WESP options defined in future) within the and any other WESP options defined in the future) within the
encapsulated ESP header, in octets. HdrLen MUST be set to zero encapsulated ESP header, in octets. HdrLen MUST be set to zero when
when using ESP with encryption. When using integrity-only ESP, using ESP with encryption. When using integrity-only ESP, the
the following HdrLen values are invalid: any value less than 12; following HdrLen values are invalid: any value less than 12; any
any value that is not a multiple of 4; any value that is not a value that is not a multiple of 4; any value that is not a multiple
multiple of 8 when using IPv6. The receiver MUST ensure that of 8 when using IPv6. The receiver MUST ensure that this field
this field matches with the header offset computed from using matches with the header offset computed from using the negotiated
the negotiated SA and MUST drop the packet in case it does not Security Association (SA) and MUST drop the packet in case it does
match. not match.
TrailerLen, 8 bits: TrailerLen contains the size of the ICV TrailerLen, 8 bits: TrailerLen contains the size of the Integrity
being used by the negotiated algorithms within the IPsec SA, in Check Value (ICV) being used by the negotiated algorithms within the
octets. TrailerLen MUST be set to zero when using ESP with IPsec SA, in octets. TrailerLen MUST be set to zero when using ESP
encryption. The receiver MUST only accept the packet if this with encryption. The receiver MUST only accept the packet if this
field matches with the value computed from using the negotiated field matches with the value computed from using the negotiated SA.
SA. This insures that sender is not deliberately setting this This ensures that sender is not deliberately setting this value to
value to obfuscate a part of the payload from examination by a obfuscate a part of the payload from examination by a trusted
trusted intermediary device. intermediary device.
Flags, 8 bits: The bits are defined most-significant-bit (MSB) Flags, 8 bits: The bits are defined most-significant-bit (MSB) first,
first, so bit 0 is the most significant bit of the flags octet. so bit 0 is the most significant bit of the flags octet.
0 1 2 3 4 5 6 7 0 1 2 3 4 5 6 7
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
|V V|E|P| Rsvd | |V V|E|P| Rsvd |
+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+
Figure 3 Flags format Figure 3: Flags Format
Version (V), 2 bits: MUST be sent as 0 and checked by the Version (V), 2 bits: MUST be sent as 0 and checked by the receiver.
receiver. If the version is different than an expected version If the version is different than an expected version number (e.g.,
number (e.g. negotiated via the control channel), then the negotiated via the control channel), then the packet MUST be dropped
packet MUST be dropped by the receiver. Future modifications to by the receiver. Future modifications to the WESP header require a
the WESP header require a new version number. In particular, the new version number. In particular, the version of WESP defined in
version of WESP defined in this document does not allow for any this document does not allow for any extensions. However, old
extensions. However, old implementations will still be able to implementations will still be able to find the encapsulated cleartext
find the encapsulated cleartext packet using the HdrLen field packet using the HdrLen field from the WESP header, when the 'E' bit
from the WESP header, when the 'E' bit is not set. Intermediate is not set. Intermediate nodes dealing with unknown versions are not
nodes dealing with unknown versions are not necessarily able to necessarily able to parse the packet correctly. Intermediate
parse the packet correctly. Intermediate treatment of such treatment of such packets is policy dependent (e.g., it may dictate
packets is policy-dependent (e.g., it may dictate dropping such dropping such packets).
packets).
Encrypted Payload (E), 1 bit: Setting the Encrypted Payload Encrypted Payload (E), 1 bit: Setting the Encrypted Payload bit to 1
bit to 1 indicates that the WESP (and therefore ESP) payload is indicates that the WESP (and therefore ESP) payload is protected with
protected with encryption. If this bit is set to 0, then the encryption. If this bit is set to 0, then the payload is using
payload is using integrity-only ESP. Setting or clearing this integrity-only ESP. Setting or clearing this bit also impacts the
bit also impacts the value in the WESP Next Header field, as value in the WESP Next Header field, as described above. The
described above. The recipient MUST ensure consistency of this recipient MUST ensure consistency of this flag with the negotiated
flag with the negotiated policy and MUST drop the incoming policy and MUST drop the incoming packet otherwise.
packet otherwise.
Padding header (P), 1 bit: If set (value 1), the 4 octet Padding header (P), 1 bit: If set (value 1), the 4-octet padding is
padding is present. If not set (value 0), the 4 octet padding present. If not set (value 0), the 4-octet padding is absent. This
is absent. This padding MUST be used with IPv6 in order to padding MUST be used with IPv6 in order to preserve IPv6 8-octet
preserve IPv6 8-octet alignment. If WESP is being used with UDP alignment. If WESP is being used with UDP encapsulation (see Section
encapsulation (see 2.1 below) and IPv6, the Protocol Identifier 2.1 below) and IPv6, the Protocol Identifier (0x00000002) occupies 4
(0x00000002) occupies four octets so the IPv6 padding is not octets so the IPv6 padding is not needed, as the header is already on
needed, as the header is already on an 8-octet boundary. This an 8-octet boundary. This padding MUST NOT be used with IPv4, as it
padding MUST NOT be used with IPv4, as it is not needed to is not needed to guarantee 4-octet IPv4 alignment.
guarantee 4-octet IPv4 alignment.
Rsvd, 4 bits: Reserved for future use. The reserved bits Rsvd, 4 bits: Reserved for future use. The reserved bits MUST be
MUST be sent as 0, and ignored by the receiver. Future documents sent as 0, and ignored by the receiver. Future documents defining
defining any of these bits MUST NOT affect the distinction any of these bits MUST NOT affect the distinction between encrypted
between encrypted and unencrypted packets or the semantics of and unencrypted packets or the semantics of HdrLen. In other words,
HdrLen. In other words, even if new bits are defined, old even if new bits are defined, old implementations will be able to
implementations will be able to find the encapsulated packet find the encapsulated packet correctly. Intermediate nodes dealing
correctly. Intermediate nodes dealing with unknown reserved bits with unknown reserved bits are not necessarily able to parse the
are not necessarily able to parse the packet correctly. packet correctly. Intermediate treatment of such packets is policy
Intermediate treatment of such packets is policy-dependent dependent (e.g., it may dictate dropping such packets).
(e.g., it may dictate dropping such packets).
Future versions of this protocol may change the version number Future versions of this protocol may change the version number and/or
and/or the reserved bits sent, possibly by negotiating them over the reserved bits sent, possibly by negotiating them over the control
the control channel. channel.
As can be seen, the WESP format extends the standard ESP header As can be seen, the WESP format extends the standard ESP header by
by the first 4 octets for IPv4 and optionally (see above) by 8 the first 4 octets for IPv4 and optionally (see above) by 8 octets
octets for IPv6. for IPv6.
2.1. UDP Encapsulation 2.1. UDP Encapsulation
This section describes a mechanism for running the new packet This section describes a mechanism for running the new packet format
format over the existing UDP encapsulation of ESP as defined in over the existing UDP encapsulation of ESP as defined in RFC 3948.
RFC 3948. This allows leveraging the existing IKE negotiation of This allows leveraging the existing IKE negotiation of the UDP port
the UDP port for NAT-T discovery and usage [RFC3947, RFC4306], for Network Address Translation Traversal (NAT-T) discovery and usage
as well as preserving the existing UDP ports for ESP (port [RFC3947] [RFC4306], as well as preserving the existing UDP ports for
4500). With UDP encapsulation, the packet format can be ESP (port 4500). With UDP encapsulation, the packet format can be
depicted as follows. depicted as follows.
0 1 2 3 0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Src Port (4500) | Dest Port (4500) | | Src Port (4500) | Dest Port (4500) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Length | Checksum | | Length | Checksum |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Protocol Identifier (value = 0x00000002) | | Protocol Identifier (value = 0x00000002) |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Next Header | HdrLen | TrailerLen | Flags | | Next Header | HdrLen | TrailerLen | Flags |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| Existing ESP Encapsulation | | Existing ESP Encapsulation |
~ ~ ~ ~
| | | |
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+ +-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
Figure 4 UDP-Encapsulated WESP Header Figure 4: UDP-Encapsulated WESP Header
Where: Where:
Source/Destination port (4500) and checksum: describes the UDP Source/Destination port (4500) and checksum: describes the UDP
encapsulation header, per RFC3948. encapsulation header, per RFC 3948.
Protocol Identifier: new field to demultiplex between UDP Protocol Identifier: new field to demultiplex between UDP
encapsulation of IKE, UDP encapsulation of ESP per RFC 3948, and encapsulation of IKE, UDP encapsulation of ESP per RFC 3948, and the
the UDP encapsulation in this specification. UDP encapsulation in this specification.
According to RFC 3948, clause 2.2, a 4 octet value of zero (0) According to RFC 3948, Section 2.2, a 4-octet value of zero (0)
immediately following the UDP header indicates a Non-ESP marker, immediately following the UDP header indicates a Non-ESP marker,
which can be used to assume that the data following that value which can be used to assume that the data following that value is an
is an IKE packet. Similarly, a value greater then 255 indicates IKE packet. Similarly, a value greater then 255 indicates that the
that the packet is an ESP packet and the 4-octet value can be packet is an ESP packet and the 4-octet value can be treated as the
treated as the ESP SPI. However, RFC 4303, clause 2.1 indicates ESP Security Parameter Index (SPI). However, RFC 4303, Section 2.1
that the values 1-255 are reserved and cannot be used as the indicates that the values 1-255 are reserved and cannot be used as
SPI. We leverage that knowledge and use one of these reserved the SPI. We leverage that knowledge and use one of these reserved
values to indicate that the UDP encapsulated ESP header contains values to indicate that the UDP encapsulated ESP header contains this
this new packet format for ESP encapsulation. new packet format for ESP encapsulation.
The remaining fields in the packet have the same meaning as per The remaining fields in the packet have the same meaning as per
section 2 above. Section 2 above.
2.2. Transport and Tunnel Mode Considerations 2.2. Transport and Tunnel Mode Considerations
This extension is equally applicable to transport and tunnel mode This extension is equally applicable to transport and tunnel mode
where the ESP Next Header field is used to differentiate between where the ESP Next Header field is used to differentiate between
these modes, as per the existing IPsec specifications. these modes, as per the existing IPsec specifications.
2.2.1. Transport Mode Processing 2.2.1. Transport Mode Processing
In transport mode, ESP is inserted after the IP header and before a In transport mode, ESP is inserted after the IP header and before a
next layer protocol, e.g., TCP, UDP, ICMP, etc. The following next layer protocol, e.g., TCP, UDP, ICMP, etc. The following
diagrams illustrate how WESP is applied to the ESP transport mode for diagrams illustrate how WESP is applied to the ESP transport mode for
a typical packet, on a "before and after" basis. a typical packet, on a "before and after" basis.
BEFORE APPLYING WESP -IPv4 BEFORE APPLYING WESP -IPv4
------------------------------------------------- -------------------------------------------------
|orig IP hdr | ESP | | | ESP | ESP| |orig IP hdr | ESP | | | ESP | ESP|
|(any options)| Hdr | TCP | Data | Trailer | ICV| |(any options)| Hdr | TCP | Data | Trailer | ICV|
------------------------------------------------- -------------------------------------------------
|<---- encryption ---->| |<---- encryption ---->|
|<------- integrity -------->| |<------- integrity -------->|
AFTER APPLYING WESP - IPv4 AFTER APPLYING WESP - IPv4
-------------------------------------------------------- --------------------------------------------------------
|orig IP hdr | WESP | ESP | | | ESP | ESP| |orig IP hdr | WESP | ESP | | | ESP | ESP|
|(any options)| Hdr | Hdr | TCP | Data | Trailer | ICV| |(any options)| Hdr | Hdr | TCP | Data | Trailer | ICV|
-------------------------------------------------------- --------------------------------------------------------
|<---- encryption ---->| |<---- encryption ---->|
|<------- integrity -------->| |<------- integrity -------->|
BEFORE APPLYING WESP - IPv6 BEFORE APPLYING WESP - IPv6
-------------------------------------------------------------- --------------------------------------------------------------
| orig |hop-by-hop,dest*,| |dest| | | ESP | ESP| | orig |hop-by-hop,dest*,| |dest| | | ESP | ESP|
|IP hdr|routing,fragment.|ESP|opt*|TCP|Data|Trailer| ICV| |IP hdr|routing,fragment |ESP|opt*|TCP|Data|Trailer| ICV|
-------------------------------------------------------------- --------------------------------------------------------------
|<---- encryption --->| |<---- encryption --->|
|<----- integrity ------->| |<----- integrity ------->|
AFTER APPLYING WESP - IPv6 AFTER APPLYING WESP - IPv6
-------------------------------------------------------------- --------------------------------------------------------------
| orig |hop-by-hop,dest*,| | |dest| | | ESP | ESP| | orig |hop-by-hop,dest*,| | |dest| | | ESP | ESP|
|IP hdr|routing,fragment.|WESP|ESP|opt*|TCP|Data|Trailer| ICV| |IP hdr|routing,fragment |WESP|ESP|opt*|TCP|Data|Trailer| ICV|
-------------------------------------------------------------- --------------------------------------------------------------
|<---- encryption --->| |<---- encryption --->|
|<----- integrity ------->| |<----- integrity ------->|
* = if present, could be before WESP, after ESP, or both * = if present, could be before WESP, after ESP, or both
All other considerations are as per RFC 4303. All other considerations are as per RFC 4303.
2.2.2. Tunnel Mode Processing 2.2.2. Tunnel Mode Processing
In tunnel mode, ESP is inserted after the new IP header and before In tunnel mode, ESP is inserted after the new IP header and before
the original IP header, as per RFC 4303. The following diagram the original IP header, as per RFC 4303. The following diagram
illustrates how WESP is applied to the ESP tunnel mode for a typical illustrates how WESP is applied to the ESP tunnel mode for a typical
packet, on a "before and after" basis. packet, on a "before-and-after" basis.
BEFORE APPLYING WESP - IPv4
---------------------------------------------------------
|new IP hdr* | | orig IP hdr* | | | ESP | ESP|
|(any options)|ESP| (any options) |TCP|Data|Trailer| ICV|
---------------------------------------------------------
|<--------- encryption --------->|
|<----------- integrity ------------>|
AFTER APPLYING WESP - IPv4
--------------------------------------------------------------
|new IP hdr* | | | orig IP hdr* | | | ESP | ESP|
|(any options)|WESP|ESP| (any options) |TCP|Data|Trailer| ICV|
--------------------------------------------------------------
|<--------- encryption --------->|
|<----------- integrity ------------>|
BEFORE APPLYING WESP - IPv6 BEFORE APPLYING WESP - IPv4
----------------------------------------------------------------- ---------------------------------------------------------
| new* |new ext | | orig*|orig ext | | | ESP | ESP| |new IP hdr* | | orig IP hdr* | | | ESP | ESP|
|IP hdr| hdrs* |ESP|IP hdr| hdrs * |TCP|Data|Trailer| ICV| |(any options)|ESP| (any options) |TCP|Data|Trailer| ICV|
----------------------------------------------------------------- ---------------------------------------------------------
|<--------- encryption ---------->| |<--------- encryption --------->|
|<------------- integrity ----------->| |<----------- integrity ------------>|
AFTER APPLYING WESP - IPv6 AFTER APPLYING WESP - IPv4
----------------------------------------------------------------- --------------------------------------------------------------
| new* |new ext | | | orig*|orig ext | | | ESP | ESP| |new IP hdr* | | | orig IP hdr* | | | ESP | ESP|
|IP hdr| hdrs* |WESP|ESP|IP hdr| hdrs * |TCP|Data|Trailer| ICV| |(any options)|WESP|ESP| (any options) |TCP|Data|Trailer| ICV|
----------------------------------------------------------------- --------------------------------------------------------------
|<--------- encryption ---------->| |<--------- encryption --------->|
|<------------- integrity ----------->| |<----------- integrity ------------>|
* = if present, construction of outer IP hdr/extensions and BEFORE APPLYING WESP - IPv6
-----------------------------------------------------------------
|new IP|new ext | |orig IP|orig ext| | | ESP | ESP|
| hdr* | hdrs* |ESP| hdr* | hdrs * |TCP|Data|Trailer| ICV|
-----------------------------------------------------------------
|<--------- encryption ---------->|
|<------------- integrity ----------->|
modification of inner IP hdr/extensions is discussed in AFTER APPLYING WESP - IPv6
-----------------------------------------------------------------
|new IP|new ext | | |orig IP|orig ext| | | ESP | ESP|
| hdr* | hdrs* |WESP|ESP| hdr* | hdrs * |TCP|Data|Trailer| ICV|
-----------------------------------------------------------------
|<--------- encryption ---------->|
|<------------- integrity ----------->|
the Security Architecture document. * = if present, construction of outer IP hdr/extensions and
modification of inner IP hdr/extensions is discussed in
the Security Architecture document.
All other considerations are as per RFC 4303. All other considerations are as per RFC 4303.
2.3. IKE Considerations 2.3. IKE Considerations
This document assumes that WESP negotiation is performed using This document assumes that WESP negotiation is performed using IKEv2.
IKEv2. In order to negotiate the new format of ESP encapsulation In order to negotiate the new format of ESP encapsulation via IKEv2
via IKEv2 [RFC4306], both parties need to agree to use the new [RFC4306], both parties need to agree to use the new packet format.
packet format. This can be achieved using a notification method This can be achieved using a notification method similar to
similar to USE_TRANSPORT_MODE defined in RFC 4306. USE_TRANSPORT_MODE, defined in RFC 4306.
The notification, USE_WESP_MODE (value TBD) MUST be included in The notification, USE_WESP_MODE (value 16415) MUST be included in a
a request message that also includes an SA payload requesting a request message that also includes an SA payload requesting a
CHILD_SA using ESP. It signals that the sender supports the CHILD_SA using ESP. It signals that the sender supports the WESP
WESP version defined in the current document a requests that the version defined in the current document and requests that the
CHILD_SA use WESP mode rather than ESP for the SA created. If CHILD_SA use WESP mode rather than ESP for the SA created. If the
the request is accepted, the response MUST also include a request is accepted, the response MUST also include a notification of
notification of type USE_WESP_MODE. If the responder declines type USE_WESP_MODE. If the responder declines the request, the
the request, the CHILD_SA will be established using ESP, as per CHILD_SA will be established using ESP, as per RFC 4303. If this is
RFC 4303. If this is unacceptable to the initiator, the unacceptable to the initiator, the initiator MUST delete the SA.
initiator MUST delete the SA. Note: Except when using this
option to negotiate WESP mode, all CHILD_SAs will use standard
ESP.
Negotiation of WESP in this manner preserves all other Note: Except when using this option to negotiate WESP mode, all
negotiation parameters, including NAT-T [RFC3948]. NAT-T is CHILD_SAs will use standard ESP.
wholly compatible with this wrapped frame format and can be used
as-is, without any modifications, in environments where NAT is Negotiation of WESP in this manner preserves all other negotiation
present and needs to be taken into account. parameters, including NAT-T [RFC3948]. NAT-T is wholly compatible
with this wrapped format and can be used as-is, without any
modifications, in environments where NAT is present and needs to be
taken into account.
WESP version negotiation is not introduced as part of this WESP version negotiation is not introduced as part of this
specification. If the WESP version is updated in a future specification. If the WESP version is updated in a future
specification, then that document MUST specify how the WESP specification, then that document MUST specify how the WESP version
version is negotiated. is negotiated.
3. Security Considerations 3. Security Considerations
As this document augments the existing ESP encapsulation format, As this document augments the existing ESP encapsulation format, UDP
UDP encapsulation definitions specified in RFC 3948 and IKE encapsulation definitions specified in RFC 3948 and IKE negotiation
negotiation of the new encapsulation, the security observations of the new encapsulation, the security observations made in those
made in those documents also apply here. In addition, as this documents also apply here. In addition, as this document allows
document allows intermediate device visibility into IPsec ESP intermediate device visibility into IPsec ESP encapsulated frames for
encapsulated frames for the purposes of network monitoring the purposes of network monitoring functions, care should be taken
functions, care should be taken not to send sensitive data over not to send sensitive data over connections using definitions from
connections using definitions from this document, based on this document, based on network domain/administrative policy. A
network domain/administrative policy. A strong key agreement strong key agreement protocol, such as IKEv2, together with a strong
protocol, such as IKEv2, together with a strong policy engine policy engine should be used in determining appropriate security
should be used in determining appropriate security policy for policy for the given traffic streams and data over which it is being
the given traffic streams and data over which it is being
employed. employed.
ESP is end-to-end and it will be impossible for the intermediate ESP is end-to-end and it will be impossible for the intermediate
devices to verify that all the fields in the WESP header are devices to verify that all the fields in the WESP header are correct.
correct. It is thus possible to modify the WESP header so that It is thus possible to modify the WESP header so that the packet
the packet sneaks past a firewall if the fields in the WESP sneaks past a firewall if the fields in the WESP header are set to
header are set to something that the firewall will allow. The something that the firewall will allow. The endpoint thus must
endpoint thus must verify the sanity of the WESP header before verify the sanity of the WESP header before accepting the packet. In
accepting the packet. In an extreme case, someone colluding with an extreme case, someone colluding with the attacker, could change
the attacker, could change the WESP fields back to the original the WESP fields back to the original values so that the attack goes
values so that the attack goes unnoticed. However, this is not a unnoticed. However, this is not a new problem and it already exists
new problem and it already exists IPsec. IPsec.
4. IANA Considerations 4. IANA Considerations
The WESP protocol number is assigned by IANA out of the IP The WESP protocol number assigned by IANA out of the IP Protocol
Protocol Number space (and as recorded at the IANA web page at Number space is 141.
http://www.iana.org/assignments/protocol-numbers) is: TBD.
The USE_WESP_MODE notification number is assigned out of the The USE_WESP_MODE notification number assigned out of the "IKEv2
"IKEv2 Notify Message Types - Status Types" registry's 16384- Notify Message Types - Status Types" registry's 16384-40959 (Expert
40959 (Expert Review) range: TBD. Review) range is 16415.
The SPI value of 2 is assigned by IANA out of the reserved SPI The SPI value of 2 has been assigned by IANA out of the reserved SPI
range from the SPI values registry to indicate use of the WESP range from the SPI values registry to indicate use of the WESP
protocol within a UDP encapsulated, NAT-T environment. protocol within a UDP-encapsulated, NAT-T environment.
This specification requests that IANA create a new registry for IANA has created a new registry for "WESP Flags" to be managed as
"WESP Flags" to be managed as follows: follows:
The first 2 bits are the WESP Version Number. The value 0 is The first 2 bits are the WESP Version Number. The value 0 is
assigned to the version defined in this specification. Further assigned to the version defined in this specification. Further
assignments of the WESP Version Number are to be managed via the assignments of the WESP Version Number are to be managed via the IANA
IANA Policy of "Standards Action" [RFC5226]. For WESP version Policy of "Standards Action" [RFC5226]. For WESP version numbers,
numbers, the unassigned values are 1, 2 and 3. The Encrypted the unassigned values are 1, 2, and 3. The Encrypted Payload bit is
Payload bit is used to indicate if the payload is encrypted or used to indicate if the payload is encrypted or using integrity-only
using integrity-only ESP. The Padding Present bit is used to ESP. The Padding Present bit is used to signal the presence of
signal the presence of padding. The remaining 4 bits of the WESP padding. The remaining 4 bits of the WESP Flags are undefined and
Flags are undefined and future assignment is to be managed via future assignment is to be managed via the IANA Policy of "IETF
the IANA Policy of "IETF Review" [RFC5226]. Review" [RFC5226].
5. Acknowledgments 5. Acknowledgments
The authors would like to acknowledge the following people for The authors would like to acknowledge the following people for their
their feedback on updating the definitions in this document. feedback on updating the definitions in this document:
David McGrew, Brian Weis, Philippe Joubert, Brian Swander, Yaron David McGrew, Brian Weis, Philippe Joubert, Brian Swander, Yaron
Sheffer, Pasi Eronen, Men Long, David Durham, Prashant Dewan, Sheffer, Pasi Eronen, Men Long, David Durham, Prashant Dewan, Marc
Marc Millier, Russ Housley, Jari Arkko among others. Millier, Russ Housley, and Jari Arkko, among others.
This document was prepared using 2-Word-v2.0.template.doc. Manav Bhatia would also like to acknowledge Swati and Maitri for
their continued support.
6. References 6. References
6.1. Normative References 6.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate [RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997. Requirement Levels", BCP 14, RFC 2119, March 1997.
[RFC2410] Glenn, R. and Kent, S., "The NULL Encryption Algorithm [RFC2410] Glenn, R. and S. Kent, "The NULL Encryption Algorithm
and Its Use With IPsec", RFC 2410, November 1998. and Its Use With IPsec", RFC 2410, November 1998.
[RFC3948] Huttunen, A., Swander, B., Volpe, V., DiBurro, L., and [RFC3948] Huttunen, A., Swander, B., Volpe, V., DiBurro, L., and
M. Stenberg, "UDP Encapsulation of IPsec ESP Packets", M. Stenberg, "UDP Encapsulation of IPsec ESP Packets",
RFC 3948, January 2005. RFC 3948, January 2005.
[RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", [RFC4303] Kent, S., "IP Encapsulating Security Payload (ESP)", RFC
RFC 4303, December 2005. 4303, December 2005.
[RFC4543] McGrew, D. and Viega J., "The Use of Galois Message [RFC4543] McGrew, D. and J. Viega, "The Use of Galois Message
Authentication Code (GMAC) in IPsec ESP and AH", RFC Authentication Code (GMAC) in IPsec ESP and AH", RFC
4543, May 2006. 4543, May 2006.
[RFC5226] Narten, T., Alverstrand, H., "Guidelines for Writing [RFC5226] Narten, T. and H. Alvestrand, "Guidelines for Writing an
an IANA Considerations Section in RFCs", RFC 5226, IANA Considerations Section in RFCs", BCP 26, RFC 5226,
May 2008. May 2008.
6.2. Informative References 6.2. Informative References
[RFC3947] Kivinen, T., Swander, B., Huttunen, A., and V. Volpe, [RFC3947] Kivinen, T., Swander, B., Huttunen, A., and V. Volpe,
"Negotiation of NAT-Traversal in the IKE", RFC 3947, "Negotiation of NAT-Traversal in the IKE", RFC 3947,
January 2005. January 2005.
[RFC4302] Kent, S., "IP Authentication Header", RFC 4302, [RFC4302] Kent, S., "IP Authentication Header", RFC 4302, December
December 2005. 2005.
[RFC4306] Kaufman, C., "Internet Key Exchange (IKEv2) Protocol", [RFC4306] Kaufman, C., Ed., "Internet Key Exchange (IKEv2)
RFC 4306, December 2005. Protocol", RFC 4306, December 2005.
[Heuristics I-D] Kivinen, T., McDonald, D., "Heuristics for Detecting [Heuristics] Kivinen, T. and D. McDonald, "Heuristics for Detecting
ESP-NULL packets", Internet Draft, April 2009. ESP-NULL packets", Work in Progress, March 2010.
Author's Addresses Authors' Addresses
Ken Grewal Ken Grewal
Intel Corporation Intel Corporation
2111 NE 25th Avenue, JF3-232 2111 NE 25th Avenue, JF3-232
Hillsboro, OR 97124 Hillsboro, OR 97124
USA USA
Phone: EMail: ken.grewal@intel.com
Email: ken.grewal@intel.com
Gabriel Montenegro Gabriel Montenegro
Microsoft Corporation Microsoft Corporation
One Microsoft Way One Microsoft Way
Redmond, WA 98052 Redmond, WA 98052
USA USA
Phone: EMail: gabriel.montenegro@microsoft.com
Email: gabriel.montenegro@microsoft.com
Manav Bhatia Manav Bhatia
Alcatel-Lucent Alcatel-Lucent
Manyata Embassy Manyata Embassy
Nagawara Bangalore Nagawara Bangalore
India India
Phone: EMail: manav.bhatia@alcatel-lucent.com
Email: manav.bhatia@alcatel-lucent.com
 End of changes. 113 change blocks. 
502 lines changed or deleted 474 lines changed or added

This html diff was produced by rfcdiff 1.38. The latest version is available from http://tools.ietf.org/tools/rfcdiff/