draft-ietf-ipsecme-failure-detection-05.txt   draft-ietf-ipsecme-failure-detection-06.txt 
IPsecME Working Group Y. Nir, Ed. IPsecME Working Group Y. Nir, Ed.
Internet-Draft Check Point Internet-Draft Check Point
Intended status: Standards Track D. Wierbowski Intended status: Standards Track D. Wierbowski
Expires: August 22, 2011 IBM Expires: September 11, 2011 IBM
F. Detienne F. Detienne
P. Sethi P. Sethi
Cisco Cisco
February 18, 2011 March 10, 2011
A Quick Crash Detection Method for IKE A Quick Crash Detection Method for IKE
draft-ietf-ipsecme-failure-detection-05 draft-ietf-ipsecme-failure-detection-06
Abstract Abstract
This document describes an extension to the IKEv2 protocol that This document describes an extension to the IKEv2 protocol that
allows for faster detection of SA desynchronization using a saved allows for faster detection of SA desynchronization using a saved
token. token.
When an IPsec tunnel between two IKEv2 peers is disconnected due to a When an IPsec tunnel between two IKEv2 peers is disconnected due to a
restart of one peer, it can take as much as several minutes for the restart of one peer, it can take as much as several minutes for the
other peer to discover that the reboot has occurred, thus delaying other peer to discover that the reboot has occurred, thus delaying
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
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Drafts is at http://datatracker.ietf.org/drafts/current/. Drafts is at http://datatracker.ietf.org/drafts/current/.
Internet-Drafts are draft documents valid for a maximum of six months Internet-Drafts are draft documents valid for a maximum of six months
and may be updated, replaced, or obsoleted by other documents at any and may be updated, replaced, or obsoleted by other documents at any
time. It is inappropriate to use Internet-Drafts as reference time. It is inappropriate to use Internet-Drafts as reference
material or to cite them other than as "work in progress." material or to cite them other than as "work in progress."
This Internet-Draft will expire on August 22, 2011. This Internet-Draft will expire on September 11, 2011.
Copyright Notice Copyright Notice
Copyright (c) 2011 IETF Trust and the persons identified as the Copyright (c) 2011 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
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8. Operational Considerations . . . . . . . . . . . . . . . . . . 14 8. Operational Considerations . . . . . . . . . . . . . . . . . . 14
8.1. Who should implement this specification . . . . . . . . . 14 8.1. Who should implement this specification . . . . . . . . . 14
8.2. Response to unknown child SPI . . . . . . . . . . . . . . 15 8.2. Response to unknown child SPI . . . . . . . . . . . . . . 15
9. Security Considerations . . . . . . . . . . . . . . . . . . . 16 9. Security Considerations . . . . . . . . . . . . . . . . . . . 16
9.1. QCD Token Generation and Handling . . . . . . . . . . . . 16 9.1. QCD Token Generation and Handling . . . . . . . . . . . . 16
9.2. QCD Token Transmission . . . . . . . . . . . . . . . . . 17 9.2. QCD Token Transmission . . . . . . . . . . . . . . . . . 17
9.3. QCD Token Enumeration . . . . . . . . . . . . . . . . . . 17 9.3. QCD Token Enumeration . . . . . . . . . . . . . . . . . . 17
10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18 10. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 18
11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18 11. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 18
12. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 18 12. Change Log . . . . . . . . . . . . . . . . . . . . . . . . . . 18
12.1. Changes from draft-ietf-ipsecme-failure-detection-04 . . 18 12.1. Changes from draft-ietf-ipsecme-failure-detection-05 . . 18
12.2. Changes from draft-ietf-ipsecme-failure-detection-03 . . 19 12.2. Changes from draft-ietf-ipsecme-failure-detection-04 . . 19
12.3. Changes from draft-ietf-ipsecme-failure-detection-02 . . 19 12.3. Changes from draft-ietf-ipsecme-failure-detection-03 . . 19
12.4. Changes from draft-ietf-ipsecme-failure-detection-01 . . 19 12.4. Changes from draft-ietf-ipsecme-failure-detection-02 . . 19
12.5. Changes from draft-ietf-ipsecme-failure-detection-00 . . 19 12.5. Changes from draft-ietf-ipsecme-failure-detection-01 . . 19
12.6. Changes from draft-nir-ike-qcd-07 . . . . . . . . . . . . 19 12.6. Changes from draft-ietf-ipsecme-failure-detection-00 . . 19
12.7. Changes from draft-nir-ike-qcd-03 and -04 . . . . . . . . 20 12.7. Changes from draft-nir-ike-qcd-07 . . . . . . . . . . . . 19
12.8. Changes from draft-nir-ike-qcd-02 . . . . . . . . . . . . 20 12.8. Changes from draft-nir-ike-qcd-03 and -04 . . . . . . . . 20
12.9. Changes from draft-nir-ike-qcd-01 . . . . . . . . . . . . 20 12.9. Changes from draft-nir-ike-qcd-02 . . . . . . . . . . . . 20
12.10. Changes from draft-nir-ike-qcd-00 . . . . . . . . . . . . 20 12.10. Changes from draft-nir-ike-qcd-01 . . . . . . . . . . . . 20
12.11. Changes from draft-nir-qcr-00 . . . . . . . . . . . . . . 20 12.11. Changes from draft-nir-ike-qcd-00 . . . . . . . . . . . . 20
13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 20 12.12. Changes from draft-nir-qcr-00 . . . . . . . . . . . . . . 20
13.1. Normative References . . . . . . . . . . . . . . . . . . 20 13. References . . . . . . . . . . . . . . . . . . . . . . . . . . 21
13.1. Normative References . . . . . . . . . . . . . . . . . . 21
13.2. Informative References . . . . . . . . . . . . . . . . . 21 13.2. Informative References . . . . . . . . . . . . . . . . . 21
Appendix A. The Path Not Taken . . . . . . . . . . . . . . . . . 21 Appendix A. The Path Not Taken . . . . . . . . . . . . . . . . . 21
A.1. Initiating a new IKE SA . . . . . . . . . . . . . . . . . 21 A.1. Initiating a new IKE SA . . . . . . . . . . . . . . . . . 21
A.2. SIR . . . . . . . . . . . . . . . . . . . . . . . . . . . 21 A.2. SIR . . . . . . . . . . . . . . . . . . . . . . . . . . . 22
A.3. Birth Certificates . . . . . . . . . . . . . . . . . . . 22 A.3. Birth Certificates . . . . . . . . . . . . . . . . . . . 22
A.4. Reducing Liveness Check Length . . . . . . . . . . . . . 22 A.4. Reducing Liveness Check Length . . . . . . . . . . . . . 22
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 22 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 23
1. Introduction 1. Introduction
IKEv2, as described in [RFC5996] and its predecessor RFC 4306, has a IKEv2, as described in [RFC5996] and its predecessor RFC 4306, has a
method for recovering from a reboot of one peer. As long as traffic method for recovering from a reboot of one peer. As long as traffic
flows in both directions, the rebooted peer should re-establish the flows in both directions, the rebooted peer should re-establish the
tunnels immediately. However, in many cases the rebooted peer is a tunnels immediately. However, in many cases the rebooted peer is a
VPN gateway that protects only servers, or else the non-rebooted peer VPN gateway that protects only servers, so all traffic is inbound.
has a dynamic IP address. In such cases, the rebooted peer will not In other cases, the non-rebooted peer has a dynamic IP address, so
be able to re-establish the tunnels. Section 2 describes how the rebooted peer cannot initiate IKE because its current IP address
recovery works under RFC 5996, and explains why it may take several is unknown. In such cases, the rebooted peer will not be able to re-
minutes. establish the tunnels. Section 2 describes how recovery works under
RFC 5996, and explains why it may take several minutes.
The method proposed here, is to send an octet string, called a "QCD The method proposed here, is to send an octet string, called a "QCD
token" in the IKE_AUTH exchange that establishes the tunnel. That token" in the IKE_AUTH exchange that establishes the tunnel. That
token can be stored on the peer as part of the IKE SA. After a token can be stored on the peer as part of the IKE SA. After a
reboot, the rebooted implementation can re-generate the token, and reboot, the rebooted implementation can re-generate the token, and
send it to the peer, so as to delete the IKE SA. Deleting the IKE SA send it to the peer, so as to delete the IKE SA. Deleting the IKE SA
results is a quick establishment of new IPsec tunnels. This is results in a quick establishment of new IPsec tunnels. This is
described in Section 3. described in Section 3.
1.1. Conventions Used in This Document 1.1. Conventions Used in This Document
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT", The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this "SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [RFC2119]. document are to be interpreted as described in [RFC2119].
The term "token" refers to an octet string that an implementation can The term "token" refers to an octet string that an implementation can
generate using only the properties of a protected IKE message (such generate using only the properties of a protected IKE message (such
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is not sending any packets anymore while it is still rebooting or is not sending any packets anymore while it is still rebooting or
recovering from the situation. recovering from the situation.
This means that the several minutes recovery period is overlaping the This means that the several minutes recovery period is overlaping the
actual recover time of the other peer, i.e., if the security gateway actual recover time of the other peer, i.e., if the security gateway
requires several minutes to boot up from the crash then the other requires several minutes to boot up from the crash then the other
peers have already finished their liveness checks before the crashing peers have already finished their liveness checks before the crashing
peer even has a chance to send INVALID_SPI notifications. peer even has a chance to send INVALID_SPI notifications.
There are cases where the peer loses state and is able to recover There are cases where the peer loses state and is able to recover
immediately; in those cases it might take several minutes to recover. immediately; in those cases it might take several minutes to recreate
the IPsec SAs.
Note that the IKEv2 specification specifically gives no guidance for Note that the IKEv2 specification specifically gives no guidance for
the number of retries or the length of timeouts, as these do not the number of retries or the length of timeouts, as these do not
affect interoperability. This means that implementations are allowed affect interoperability. This means that implementations are allowed
to use the hints provided by the INVALID_SPI messages to shorten to use the hints provided by the INVALID_SPI messages to shorten
those timeouts (i.e., different environment and situation requiring those timeouts (i.e., different environment and situation requiring
different rules). different rules).
Some existing IKEv2 implementations already do that (i.e., both Some existing IKEv2 implementations already do that (i.e., both
shorten timeouts or limit number of retries) based on these kind of shorten timeouts or limit number of retries) based on these kind of
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QCD token generated by an implementation. Cryptographic QCD token generated by an implementation. Cryptographic
mechanisms such as PRNG and hash functions are RECOMMENDED. mechanisms such as PRNG and hash functions are RECOMMENDED.
o The token maker MUST be able to re-generate or retrieve the token o The token maker MUST be able to re-generate or retrieve the token
based on the IKE SPIs even after it reboots. based on the IKE SPIs even after it reboots.
o The method of token generation MUST be such that a collision of o The method of token generation MUST be such that a collision of
QCD tokens between different pairs of IKE SPI will be highly QCD tokens between different pairs of IKE SPI will be highly
unlikely. unlikely.
5.1. A Stateless Method of Token Generation 5.1. A Stateless Method of Token Generation
This describes a stateless method of generating a token: The following describes a stateless method of generating a token. In
this case, 'stateless' means not maintaining any per-tunnel state,
although there is a small amount of non-volatile storage required.
o At installation or immediately after the first boot of the token o At installation or immediately after the first boot of the token
maker, 32 random octets are generated using a secure random number maker, 32 random octets are generated using a secure random number
generator or a PRNG. generator or a PRNG.
o Those 32 bytes, called the "QCD_SECRET", are stored in non- o Those 32 bytes, called the "QCD_SECRET", are stored in non-
volatile storage on the machine, and kept indefinitely. volatile storage on the machine, and kept indefinitely.
o If key rollover is required by policy, the implementation MAY o If key rollover is required by policy, the implementation MAY
periodically generate a new QCD_SECRET and keep up to 3 previous periodically generate a new QCD_SECRET and keep up to 3 previous
generations. When sending an unprotected QCD_TOKEN, as many as 4 generations. When sending an unprotected QCD_TOKEN, as many as 4
notification payloads may be sent, each from a different notification payloads may be sent, each from a different
QCD_SECRET. QCD_SECRET.
o The TOKEN_SECRET_DATA is calculated as follows: o The TOKEN_SECRET_DATA is calculated as follows:
TOKEN_SECRET_DATA = HASH(QCD_SECRET | SPI-I | SPI-R) TOKEN_SECRET_DATA = HASH(QCD_SECRET | SPI-I | SPI-R)
5.2. A Stateless Method with IP addresses 5.2. A Stateless Method with IP addresses
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configurations typically fall in this category. In order for a load configurations typically fall in this category. In order for a load
balancing configuration of IPsec gateways to support this balancing configuration of IPsec gateways to support this
specification, all members MUST be able to tell whether a particular specification, all members MUST be able to tell whether a particular
IKE SA is active anywhere in the cluster. One way to do it is to IKE SA is active anywhere in the cluster. One way to do it is to
synchronize a list of active IKE SPIs among all the cluster members. synchronize a list of active IKE SPIs among all the cluster members.
Because it includes the token taker's IP address in the token Because it includes the token taker's IP address in the token
generation, the method in Section 5.2 can (under certain conditions) generation, the method in Section 5.2 can (under certain conditions)
prevent revealing the QCD token for an existing pair of IKE SPIs to prevent revealing the QCD token for an existing pair of IKE SPIs to
an attacker who is using a different IP address, even in a load- an attacker who is using a different IP address, even in a load-
sharing cluster without state synchronization. This method does not sharing cluster without state synchronization. That method does not
prevent revealing the QCD token to an active attacker who is spoofing prevent revealing the QCD token to an active attacker who is spoofing
the token taker's IP address. Such an attacker may attempt to direct the token taker's IP address. Such an attacker may attempt to direct
messages to a cluster member other than the member responsible for messages to a cluster member other than the member responsible for
the IKE SA in an attempt to trick that gateway into sending a QCD the IKE SA in an attempt to trick that gateway into sending a QCD
token for a valid IKE SA. This method should not be used unless the token for a valid IKE SA. That method should not be used unless the
load balancer guarantees that IKE packets from the same source IP load balancer guarantees that IKE packets from the same source IP
address always go to the same cluster member. address always go to the same cluster member.
9.3. QCD Token Enumeration 9.3. QCD Token Enumeration
An attacker may try to attack QCD if the generation algorithm An attacker may try to attack QCD if the generation algorithm
described in Section 5.1 is used. The attacker will send several described in Section 5.1 is used. The attacker will send several
fake IKE requests to the gateway under attack, receiving and fake IKE requests to the gateway under attack, receiving and
recording the QCD Tokens in the responses. This will allow the recording the QCD Tokens in the responses. This will allow the
attacker to create a dictionary of IKE SPIs to QCD Tokens, which can attacker to create a dictionary of IKE SPIs to QCD Tokens, which can
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types range (16406-40959) of the "IKEv2 Notify Message Types" types range (16406-40959) of the "IKEv2 Notify Message Types"
registry with name "QUICK_CRASH_DETECTION". registry with name "QUICK_CRASH_DETECTION".
11. Acknowledgements 11. Acknowledgements
We would like to thank Hannes Tschofenig and Yaron Sheffer for their We would like to thank Hannes Tschofenig and Yaron Sheffer for their
comments about Session Resumption. comments about Session Resumption.
Others who have contributed valuable comments are, in alphabetical Others who have contributed valuable comments are, in alphabetical
order, Lakshminath Dondeti, Paul Hoffman, Tero Kivinen, Scott C order, Lakshminath Dondeti, Paul Hoffman, Tero Kivinen, Scott C
Moonen, and Keith Welter. Moonen, Magnus Nystrom, and Keith Welter.
12. Change Log 12. Change Log
This section lists all changes in this document This section lists all changes in this document
NOTE TO RFC EDITOR : Please remove this section in the final RFC NOTE TO RFC EDITOR : Please remove this section in the final RFC
12.1. Changes from draft-ietf-ipsecme-failure-detection-04 12.1. Changes from draft-ietf-ipsecme-failure-detection-05
o Some clarifications suggested by Magnus Nystrom.
12.2. Changes from draft-ietf-ipsecme-failure-detection-04
o Some more rephrasing of section 9.2 based on suggestions by Tero o Some more rephrasing of section 9.2 based on suggestions by Tero
Kivinen and Dave Wierbowski. Kivinen and Dave Wierbowski.
12.2. Changes from draft-ietf-ipsecme-failure-detection-03 12.3. Changes from draft-ietf-ipsecme-failure-detection-03
o Merged section 9.4 into section 9.2. o Merged section 9.4 into section 9.2.
o Multiple typos discovered by Scott Moonen, Keith Welter and Yaron. o Multiple typos discovered by Scott Moonen, Keith Welter and Yaron.
12.3. Changes from draft-ietf-ipsecme-failure-detection-02 12.4. Changes from draft-ietf-ipsecme-failure-detection-02
o Moved section 7 to Appendix A. Also changed some wording. o Moved section 7 to Appendix A. Also changed some wording.
o Fixed some language in the "interaction with session resumption" o Fixed some language in the "interaction with session resumption"
section to say that although liveness check MUST be done, there section to say that although liveness check MUST be done, there
are no time limits to how long an implementation takes before are no time limits to how long an implementation takes before
starting liveness check, or ending it. starting liveness check, or ending it.
12.4. Changes from draft-ietf-ipsecme-failure-detection-01 12.5. Changes from draft-ietf-ipsecme-failure-detection-01
o Fixed the language requiring random IKE SPIs. o Fixed the language requiring random IKE SPIs.
o Some better explanation of the reasons to choose the methods in o Some better explanation of the reasons to choose the methods in
Section 5.2 and the method in Section 5.1, to close issue #193. Section 5.2 and the method in Section 5.1, to close issue #193.
o Added text to the beginning of Section 9 to accomodate issue #194. o Added text to the beginning of Section 9 to accomodate issue #194.
12.5. Changes from draft-ietf-ipsecme-failure-detection-00 12.6. Changes from draft-ietf-ipsecme-failure-detection-00
o Nits pointed out by Scott and Yaron. o Nits pointed out by Scott and Yaron.
o Pratima and Frederic are back on board. o Pratima and Frederic are back on board.
o Changed IKEv2bis draft reference to RFC 5996. o Changed IKEv2bis draft reference to RFC 5996.
o Resolved issues #189, #190, #191, and #192: o Resolved issues #189, #190, #191, and #192:
* Renamed section 4.5 and removed the requirement to send an * Renamed section 4.5 and removed the requirement to send an
acknowledgement for the unprotected message. acknowledgement for the unprotected message.
* Moved the QCD token from the last to the first IKE_AUTH * Moved the QCD token from the last to the first IKE_AUTH
request. request.
* Added a MUST to Section 9.3 to require that IKE SPIs be * Added a MUST to Section 9.3 to require that IKE SPIs be
randomly generated. randomly generated.
* Changed the language in Section 8.1, to not use RFC 2119 * Changed the language in Section 8.1, to not use RFC 2119
terminology. terminology.
* Moved the section describing why one would want the method * Moved the section describing why one would want the method
dependant on IP addresses (in Section 5.2 from operational dependant on IP addresses (in Section 5.2 from operational
considerations to security considerations. considerations to security considerations.
12.6. Changes from draft-nir-ike-qcd-07 12.7. Changes from draft-nir-ike-qcd-07
o First WG version. o First WG version.
o Addressed Scott C Moonen's concern about collisions of QCD tokens. o Addressed Scott C Moonen's concern about collisions of QCD tokens.
o Updated references to point to IKEv2bis instead of RFC 4306 and o Updated references to point to IKEv2bis instead of RFC 4306 and
4718. Also converted draft reference for resumption to RFC 5723. 4718. Also converted draft reference for resumption to RFC 5723.
o Added Dave Wiebrowski as author, and removed Pratima and Frederic. o Added Dave Wiebrowski as author, and removed Pratima and Frederic.
12.7. Changes from draft-nir-ike-qcd-03 and -04 12.8. Changes from draft-nir-ike-qcd-03 and -04
Mostly editorial changes and cleaning up. Mostly editorial changes and cleaning up.
12.8. Changes from draft-nir-ike-qcd-02 12.9. Changes from draft-nir-ike-qcd-02
o Described QCD token enumeration, following a question by o Described QCD token enumeration, following a question by
Lakshminath Dondeti. Lakshminath Dondeti.
o Added the ability to replace the QCD token for an existing IKE SA. o Added the ability to replace the QCD token for an existing IKE SA.
o Added tokens dependent on peer IP address and their interaction o Added tokens dependent on peer IP address and their interaction
with MOBIKE. with MOBIKE.
12.9. Changes from draft-nir-ike-qcd-01 12.10. Changes from draft-nir-ike-qcd-01
o Removed stateless method. o Removed stateless method.
o Added discussion of rekeying and resumption. o Added discussion of rekeying and resumption.
o Added discussion of non-synchronized load-balanced clusters of o Added discussion of non-synchronized load-balanced clusters of
gateways in the security considerations. gateways in the security considerations.
o Other wording fixes. o Other wording fixes.
12.10. Changes from draft-nir-ike-qcd-00 12.11. Changes from draft-nir-ike-qcd-00
o Merged proposal with draft-detienne-ikev2-recovery o Merged proposal with draft-detienne-ikev2-recovery
o Changed the protocol so that the rebooted peer generates the o Changed the protocol so that the rebooted peer generates the
token. This has the effect, that the need for persistent storage token. This has the effect, that the need for persistent storage
is eliminated. is eliminated.
o Added discussion of birth certificates. o Added discussion of birth certificates.
12.11. Changes from draft-nir-qcr-00 12.12. Changes from draft-nir-qcr-00
o Changed name to reflect that this relates to IKE. Also changed o Changed name to reflect that this relates to IKE. Also changed
from quick crash recovery to quick crash detection to avoid from quick crash recovery to quick crash detection to avoid
confusion with IFARE. confusion with IFARE.
o Added more operational considerations. o Added more operational considerations.
o Added interaction with IFARE. o Added interaction with IFARE.
o Added discussion of backup gateways. o Added discussion of backup gateways.
13. References 13. References
13.1. Normative References 13.1. 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.
[RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol [RFC4555] Eronen, P., "IKEv2 Mobility and Multihoming Protocol
(MOBIKE)", RFC 4555, June 2006. (MOBIKE)", RFC 4555, June 2006.
[RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen, [RFC5996] Kaufman, C., Hoffman, P., Nir, Y., and P. Eronen,
"Internet Key Exchange Protocol: IKEv2", RFC 5996, "Internet Key Exchange Protocol: IKEv2", RFC 5996,
 End of changes. 28 change blocks. 
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