draft-ietf-opsec-vpn-leakages-02.txt   draft-ietf-opsec-vpn-leakages-03.txt 
Operational Security Capabilities for F. Gont Operational Security Capabilities for F. Gont
IP Network Infrastructure (opsec) Huawei Technologies IP Network Infrastructure (opsec) Huawei Technologies
Internet-Draft August 23, 2013 Internet-Draft January 23, 2014
Intended status: Informational Intended status: Informational
Expires: February 24, 2014 Expires: July 27, 2014
Virtual Private Network (VPN) traffic leakages in dual-stack hosts/ Virtual Private Network (VPN) traffic leakages in dual-stack hosts/
networks networks
draft-ietf-opsec-vpn-leakages-02 draft-ietf-opsec-vpn-leakages-03
Abstract Abstract
The subtle way in which the IPv6 and IPv4 protocols co-exist in The subtle way in which the IPv6 and IPv4 protocols co-exist in
typical networks, together with the lack of proper IPv6 support in typical networks, together with the lack of proper IPv6 support in
popular Virtual Private Network (VPN) products, may inadvertently popular Virtual Private Network (VPN) products, may inadvertently
result in VPN traffic leaks. That is, traffic meant to be result in VPN traffic leaks. That is, traffic meant to be
transferred over a VPN connection may leak out of such connection and transferred over a VPN connection may leak out of such connection and
be transferred in the clear from the local network to the final be transferred in the clear from the local network to the final
destination. This document discusses some scenarios in which such destination. This document discusses some scenarios in which such
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Internet-Drafts are working documents of the Internet Engineering Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet- working documents as Internet-Drafts. The list of current Internet-
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 February 24, 2014. This Internet-Draft will expire on July 27, 2014.
Copyright Notice Copyright Notice
Copyright (c) 2013 IETF Trust and the persons identified as the Copyright (c) 2014 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 respect carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License. described in the Simplified BSD License.
Table of Contents Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3 1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. IPv4 and IPv6 co-existence . . . . . . . . . . . . . . . . . . 4 2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Virtual Private Networks in IPv4/IPv6 dual-stack 3. IPv4 and IPv6 co-existence . . . . . . . . . . . . . . . . . . 5
hosts/networks . . . . . . . . . . . . . . . . . . . . . . . . 5 4. Virtual Private Networks in IPv4/IPv6 dual-stack
4. Inadvertent VPN traffic-leakages in legitimate scenarios . . . 6 hosts/networks . . . . . . . . . . . . . . . . . . . . . . . . 6
5. VPN traffic-leakage attacks . . . . . . . . . . . . . . . . . 7 5. Inadvertent VPN traffic-leakages in legitimate scenarios . . . 7
6. Mitigations to VPN traffic-leakage vulnerabilities . . . . . . 8 6. VPN traffic-leakage attacks . . . . . . . . . . . . . . . . . 8
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 7. Mitigations to VPN traffic-leakage vulnerabilities . . . . . . 9
8. Security Considerations . . . . . . . . . . . . . . . . . . . 11 7.1. Fixing VPN client software . . . . . . . . . . . . . . . . 9
9. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 12 7.2. Operational Mitigations . . . . . . . . . . . . . . . . . 10
10. References . . . . . . . . . . . . . . . . . . . . . . . . . . 13 8. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 11
10.1. Normative References . . . . . . . . . . . . . . . . . . 13 9. Security Considerations . . . . . . . . . . . . . . . . . . . 12
10.2. Informative References . . . . . . . . . . . . . . . . . 13 10. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 13
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 15 11. References . . . . . . . . . . . . . . . . . . . . . . . . . . 14
11.1. Normative References . . . . . . . . . . . . . . . . . . . 14
11.2. Informative References . . . . . . . . . . . . . . . . . . 14
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 16
1. Introduction 1. Introduction
It is a very common practice for employees working at remote It is a very common practice for employees working at remote
locations to establish a VPN connection with their office or home locations to establish a VPN connection with their office or home
office. This is typically done to gain access to some resources only office. This is typically done to gain access to some resources only
available within the company's network, but also to secure the host's available within the company's network, but also to secure the host's
traffic against attackers that might be connected to the same remote traffic against attackers that might be connected to the same remote
location. The same is true for mobile nodes that establish VPN location. The same is true for mobile nodes that establish VPN
connections to secure their traffic while they roam from one network connections to secure their traffic while they roam from one network
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below. below.
The subtle way in which the IPv4 and IPv6 protocols interact and co- The subtle way in which the IPv4 and IPv6 protocols interact and co-
exist in dual-stacked networks might, either inadvertently or as a exist in dual-stacked networks might, either inadvertently or as a
result of a deliberate attack, result in VPN traffic leakages -- that result of a deliberate attack, result in VPN traffic leakages -- that
is, traffic meant to be transferred over a VPN connection could leak is, traffic meant to be transferred over a VPN connection could leak
out of the VPN connection and be transmitted in the clear from the out of the VPN connection and be transmitted in the clear from the
local network to the final destination, without employing the VPN local network to the final destination, without employing the VPN
services at all. services at all.
Section 2 provides some background about IPv6 and IPv4 co-existence, Section 3 provides some background about IPv6 and IPv4 co-existence,
summarizing how IPv6 and IPv4 interact on a typical dual-stacked summarizing how IPv6 and IPv4 interact on a typical dual-stacked
network. Section 3 describes the underlying problem that leads to network. Section 4 describes the underlying problem that leads to
the aforementioned VPN traffic leakages. Section 4 describes the aforementioned VPN traffic leakages. Section 5 describes
legitimate scenarios in which such traffic leakages might occur, legitimate scenarios in which such traffic leakages might occur,
while Section 5 describes how VPN traffic leakages can be triggered while Section 6 describes how VPN traffic leakages can be triggered
by deliberate attacks. by deliberate attacks.
2. IPv4 and IPv6 co-existence 2. Terminology
When employing the term VPN (or its acronym, "VPN"), this document
refers to IPsec-based or TLS-based tunnels, where traffic is
encapsulated and sent from a client to a middle-box, to access
multiple network services (potentially emplying different transport
and/or application protocols).
Our use of the term "Virtual Private Networks" excludes the so-called
SSL/TLS VPN portals (a front-end provided by the middlebox to add
security to a normally-unsecured site). Further discussion of SSL-
based VPNs can be found in [SSL-VPNs].
We note that, in addition to the general case of "send all traffic
through the VPN", this document additionally considers the so-called
"split-tunnel" case, where some subset of the traffic is sent through
the VPN, while other traffic is send to its intended destination with
a direct routing path (i.e., without employing the VPN tunnel). We
note that many organizations will prevent split-tunneling in their
VPN configurations if they would like to make sure the users data
goes through a gateway with protections (malware detection, URL
filtering, etc.), but others are more interested in performance of
the user's access or the ability for researchers to have options to
access sites they may not be able to through the gateway.
3. IPv4 and IPv6 co-existence
The co-existence of the IPv4 and IPv6 protocols has a number of The co-existence of the IPv4 and IPv6 protocols has a number of
interesting and subtle aspects that may have "surprising" interesting and subtle aspects that may have "surprising"
consequences. While IPv6 is not backwards-compatible with IPv4, the consequences. While IPv6 is not backwards-compatible with IPv4, the
two protocols are "tied" together by the Domain Name System (DNS). two protocols are "tied" together by the Domain Name System (DNS).
For example, consider a site (say, www.example.com) that has both For example, consider a site (say, www.example.com) that has both
IPv4 and IPv6 support. The corresponding domain name IPv4 and IPv6 support. The corresponding domain name
(www.example.com, in our case) will contain both A and AAAA DNS (www.example.com, in our case) will contain both A and AAAA DNS
resource records (RRs). Each A record will contain one IPv4 address, resource records (RRs). Each A record will contain one IPv4 address,
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address from a list of IPv6 and IPv4 addresses. [RFC6555] address from a list of IPv6 and IPv4 addresses. [RFC6555]
discusses the challenge of selecting the most appropriate discusses the challenge of selecting the most appropriate
destination address, along with a proposed implementation approach destination address, along with a proposed implementation approach
that mitigates connection-establishment delays. that mitigates connection-establishment delays.
As a result of this "co-existence" between IPv6 and IPv4, when a As a result of this "co-existence" between IPv6 and IPv4, when a
dual-stacked client means to communicate with some other system, the dual-stacked client means to communicate with some other system, the
availability of A and AAAA DNS resource records will typically affect availability of A and AAAA DNS resource records will typically affect
which protocol is employed to communicate with that system. which protocol is employed to communicate with that system.
3. Virtual Private Networks in IPv4/IPv6 dual-stack hosts/networks 4. Virtual Private Networks in IPv4/IPv6 dual-stack hosts/networks
Many Virtual Private Network (VPN) implementations do not support the Many Virtual Private Network (VPN) implementations do not support the
IPv6 protocol -- or, what is worse, they completely ignore IPv6. IPv6 protocol -- or, what is worse, they completely ignore IPv6.
This typically means that, when establishing a VPN connection, the This typically means that, when establishing a VPN connection, the
VPN software takes care of the IPv4 connectivity by, e.g. inserting VPN software takes care of the IPv4 connectivity by, e.g. inserting
an IPv4 default route that causes all IPv4 traffic to be sent over an IPv4 default route that causes all IPv4 traffic to be sent over
the VPN connection (as opposed to sending the traffic in the clear, the VPN connection (as opposed to sending the traffic in the clear,
employing the local router). However, if IPv6 is not supported (or employing the local router). However, if IPv6 is not supported (or
completely ignored), any packets destined to an IPv6 address will be completely ignored), any packets destined to an IPv6 address will be
sent in the clear using the local IPv6 router. That is, the VPN sent in the clear using the local IPv6 router. That is, the VPN
software will do nothing about the IPv6 traffic. software will do nothing about the IPv6 traffic.
The underlying problem here is that while IPv4 and IPv6 are two The underlying problem here is that while IPv4 and IPv6 are two
different protocols incompatible with each other, the two protocols different protocols incompatible with each other, the two protocols
are glued together by the Domain Name System. Therefore, for dual- are glued together by the Domain Name System. Therefore, for dual-
stacked systems, it is not possible to secure the communication with stacked systems, it is not possible to secure the communication with
another system without securing both protocols (IPv6 and IPv4). another system without securing both protocols (IPv6 and IPv4).
4. Inadvertent VPN traffic-leakages in legitimate scenarios 5. Inadvertent VPN traffic-leakages in legitimate scenarios
Consider a dual-stacked host that employs IPv4-only VPN software to Consider a dual-stacked host that employs IPv4-only VPN software to
establish a VPN connection with a VPN server, and that such host now establish a VPN connection with a VPN server, and that such host now
connects to a dual-stacked network (that provides both IPv6 and IPv4 connects to a dual-stacked network (that provides both IPv6 and IPv4
connectivity). If some application on the client means to connectivity). If some application on the client means to
communicate with a dual-stacked destination, the client will communicate with a dual-stacked destination, the client will
typically query both A and AAAA DNS resource records. Since the host typically query both A and AAAA DNS resource records. Since the host
will have both IPv4 and IPv6 connectivity, and the intended will have both IPv4 and IPv6 connectivity, and the intended
destination will have both A and AAAA DNS resource records, one of destination will have both A and AAAA DNS resource records, one of
the possible outcomes is that the host will employ IPv6 to the possible outcomes is that the host will employ IPv6 to
communicate with the intended destination. Since the VPN software communicate with the intended destination. Since the VPN software
does not support IPv6, the IPv6 traffic will not employ the VPN does not support IPv6, the IPv6 traffic will not employ the VPN
connection, and hence will have neither integrity nor confidentiality connection, and hence will have neither integrity nor confidentiality
protection from the source host to the final destination. protection from the source host to the final destination.
This could inadvertently expose sensitive traffic that was assumed to This could inadvertently expose sensitive traffic that was assumed to
be secured by the VPN software. In this particular scenario, the be secured by the VPN software. In this particular scenario, the
resulting VPN traffic leakage is a side-effect of employing IPv6- resulting VPN traffic leakage is a side-effect of employing IPv6-
unaware VPN software in a dual-stacked host/network. unaware VPN software in a dual-stacked host/network.
5. VPN traffic-leakage attacks 6. VPN traffic-leakage attacks
A local attacker could deliberately trigger IPv6 connectivity on the A local attacker could deliberately trigger IPv6 connectivity on the
victim host by sending forged ICMPv6 Router Advertisement messages victim host by sending forged ICMPv6 Router Advertisement messages
[RFC4861]. Such packets could be sent by employing standard software [RFC4861]. Such packets could be sent by employing standard software
such as rtadvd [RTADVD], or by employing packet-crafting tools such such as rtadvd [RTADVD], or by employing packet-crafting tools such
as [SI6-Toolkit] or THC-IPv6 [THC-IPv6]. Once IPv6 connectivity has as [SI6-Toolkit] or THC-IPv6 [THC-IPv6]. Once IPv6 connectivity has
been enabled, communications with dual-stacked systems could result been enabled, communications with dual-stacked systems could result
in VPN traffic leakages, as previously described. in VPN traffic leakages, as previously described.
While this attack may be useful enough (due to the increasing number While this attack may be useful enough (due to the increasing number
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[RFC6106], and then perform a DNS spoofing attack such that he can [RFC6106], and then perform a DNS spoofing attack such that he can
become a "Man in the Middle" and intercept the corresponding traffic. become a "Man in the Middle" and intercept the corresponding traffic.
As with the previous attack scenario, packet-crafting tools such as As with the previous attack scenario, packet-crafting tools such as
[SI6-Toolkit] and [THC-IPv6] can readily perform this attack. [SI6-Toolkit] and [THC-IPv6] can readily perform this attack.
Some systems are known to prefer IPv6-based recursive DNS servers Some systems are known to prefer IPv6-based recursive DNS servers
over IPv4-based ones, and hence the "malicious" recursive DNS over IPv4-based ones, and hence the "malicious" recursive DNS
servers would be preferred over the legitimate ones advertised by servers would be preferred over the legitimate ones advertised by
the VPN server. the VPN server.
6. Mitigations to VPN traffic-leakage vulnerabilities 7. Mitigations to VPN traffic-leakage vulnerabilities
7.1. Fixing VPN client software
There are a number of possible mitigations for the VPN traffic- There are a number of possible mitigations for the VPN traffic-
leakage vulnerability discussed in this document. leakage vulnerability discussed in this document.
If the VPN client is configured by administrative decision to If the VPN client is configured by administrative decision to
redirect all IPv4 traffic to the VPN, it should: redirect all IPv4 traffic to the VPN, it should:
1. If IPv6 is not supported in the VPN software, disable IPv6 1. If IPv6 is not supported in the VPN software, disable IPv6
support in all network interfaces. support in all network interfaces.
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(cybercafe, etc.). (cybercafe, etc.).
Besides, popular implementations of RA-Guard are known to be Besides, popular implementations of RA-Guard are known to be
vulnerable to evasion attacks vulnerable to evasion attacks
[I-D.ietf-v6ops-ra-guard-implementation]. [I-D.ietf-v6ops-ra-guard-implementation].
Finally, we note that if (eventually) IPv6-only VPN implementations Finally, we note that if (eventually) IPv6-only VPN implementations
become available, they should consider similar issues that would become available, they should consider similar issues that would
arise if they do nothing about the IPv4 traffic. arise if they do nothing about the IPv4 traffic.
7. IANA Considerations 7.2. Operational Mitigations
While the desired mtigation for the issues discussed in this document
is for VPN clients to be IPv6-aware, we note that in scenarios where
tthis would be unfeasible, and administrator may want to disable IPv6
connectivity on all network interfaces of the node employing the
IPv6-unaware VPN client.
8. IANA Considerations
This document has no actions for IANA. This document has no actions for IANA.
8. Security Considerations 9. Security Considerations
This document discusses how traffic meant to be transferred over a This document discusses how traffic meant to be transferred over a
VPN connection can leak out of the VPN, and hence appear in the clear VPN connection can leak out of the VPN, and hence appear in the clear
on the local network. This is the result of employing IPv6-unaware on the local network. This is the result of employing IPv6-unaware
VPN client software on dual-stacked hosts. VPN client software on dual-stacked hosts.
Possible ways to mitigate this problem include fixing the VPN client Possible ways to mitigate this problem include fixing the VPN client
software, or disabling IPv6 connectivity on all network interfaces software, or disabling IPv6 connectivity on all network interfaces
when the previous option is not feasible. when the previous option is not feasible.
9. Acknowledgements 10. Acknowledgements
The author would like to thank (in alphabetical order) Gert Doering The author would like to thank (in alphabetical order) Gert Doering
and Tor Houghton, who providing comments on earlier versions of this and Tor Houghton, who providing comments on earlier versions of this
document. document.
This documents has benefited from the input of Cameron Byrne, Gert This documents has benefited from the input of Cameron Byrne, Gert
Doering, Seth Hall, Tor Houghton, Alastair Johnson, Merike Kaeo, Doering, Seth Hall, Paul Hoffman, Tor Houghton, Joel Jaeggli,
Panos Kampanakis, Henrik Lund Kramshoj, Thomas Osterried, and Jim Alastair Johnson, Merike Kaeo, Panos Kampanakis, Henrik Lund
Small, while discussing this topic on the ipv6hackers mailing-list Kramshoj, Kathleen Moriarty, Thomas Osterried, and Jim Small, while
[IPv6-Hackers]. It has also benefited from discussions with Andrew discussing this topic on the ipv6hackers mailing-list [IPv6-Hackers].
Yourtchenko on the opsec wg mailing-list [OPSEC-LIST]. It has also benefited from discussions with Andrew Yourtchenko on the
opsec wg mailing-list [OPSEC-LIST].
10. References 11. References
10.1. Normative References 11.1. Normative References
[RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and [RFC4191] Draves, R. and D. Thaler, "Default Router Preferences and
More-Specific Routes", RFC 4191, November 2005. More-Specific Routes", RFC 4191, November 2005.
[RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman, [RFC4861] Narten, T., Nordmark, E., Simpson, W., and H. Soliman,
"Neighbor Discovery for IP version 6 (IPv6)", RFC 4861, "Neighbor Discovery for IP version 6 (IPv6)", RFC 4861,
September 2007. September 2007.
[RFC6106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli, [RFC6106] Jeong, J., Park, S., Beloeil, L., and S. Madanapalli,
"IPv6 Router Advertisement Options for DNS Configuration", "IPv6 Router Advertisement Options for DNS Configuration",
RFC 6106, November 2010. RFC 6106, November 2010.
[RFC6724] Thaler, D., Draves, R., Matsumoto, A., and T. Chown, [RFC6724] Thaler, D., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol Version 6 "Default Address Selection for Internet Protocol Version 6
(IPv6)", RFC 6724, September 2012. (IPv6)", RFC 6724, September 2012.
[RFC6555] Wing, D. and A. Yourtchenko, "Happy Eyeballs: Success with [RFC6555] Wing, D. and A. Yourtchenko, "Happy Eyeballs: Success with
Dual-Stack Hosts", RFC 6555, April 2012. Dual-Stack Hosts", RFC 6555, April 2012.
10.2. Informative References 11.2. Informative References
[RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J. [RFC6105] Levy-Abegnoli, E., Van de Velde, G., Popoviciu, C., and J.
Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105, Mohacsi, "IPv6 Router Advertisement Guard", RFC 6105,
February 2011. February 2011.
[I-D.ietf-v6ops-ra-guard-implementation] [I-D.ietf-v6ops-ra-guard-implementation]
Gont, F., "Implementation Advice for IPv6 Router Gont, F., "Implementation Advice for IPv6 Router
Advertisement Guard (RA-Guard)", Advertisement Guard (RA-Guard)",
draft-ietf-v6ops-ra-guard-implementation-07 (work in draft-ietf-v6ops-ra-guard-implementation-07 (work in
progress), November 2012. progress), November 2012.
[I-D.ietf-opsec-dhcpv6-shield] [I-D.ietf-opsec-dhcpv6-shield]
Gont, F., Liu, W., and G. Velde, "DHCPv6-Shield: Gont, F., Will, W., and G. Velde, "DHCPv6-Shield:
Protecting Against Rogue DHCPv6 Servers", Protecting Against Rogue DHCPv6 Servers",
draft-ietf-opsec-dhcpv6-shield-00 (work in progress), draft-ietf-opsec-dhcpv6-shield-01 (work in progress),
December 2012. October 2013.
[IPv6-Hackers] [IPv6-Hackers]
"IPv6 Hackers mailing-list", "IPv6 Hackers mailing-list",
http://lists.si6networks.com/listinfo/ipv6hackers/. http://lists.si6networks.com/listinfo/ipv6hackers/.
[OPSEC-LIST] [OPSEC-LIST]
"OPSEC WG mailing-list", "OPSEC WG mailing-list",
https://www.ietf.org/mailman/listinfo/opsec. https://www.ietf.org/mailman/listinfo/opsec.
[SI6-Toolkit] [SI6-Toolkit]
"SI6 Networks' IPv6 toolkit", "SI6 Networks' IPv6 toolkit",
<http://www.si6networks.com/tools/ipv6toolkit>. <http://www.si6networks.com/tools/ipv6toolkit>.
[THC-IPv6] [THC-IPv6]
"The Hacker's Choice IPv6 Attack Toolkit", "The Hacker's Choice IPv6 Attack Toolkit",
<http://www.thc.org/thc-ipv6/>. <http://www.thc.org/thc-ipv6/>.
[RTADVD] "rtadvd(8) manual page", <http://www.freebsd.org/cgi/ [RTADVD] "rtadvd(8) manual page", <http://www.freebsd.org/cgi/
man.cgi?query=rtadvd&sektion=8>. man.cgi?query=rtadvd&sektion=8>.
[SSL-VPNs]
Hoffman, P., "SSL VPNs: An IETF Perspective", IETF 72,
SAAG Meeting., 2008,
<http://www.ietf.org/proceedings/72/slides/saag-4.pdf>.
Author's Address Author's Address
Fernando Gont Fernando Gont
Huawei Technologies Huawei Technologies
Evaristo Carriego 2644 Evaristo Carriego 2644
Haedo, Provincia de Buenos Aires 1706 Haedo, Provincia de Buenos Aires 1706
Argentina Argentina
Phone: +54 11 4650 8472 Phone: +54 11 4650 8472
Email: fgont@si6networks.com Email: fgont@si6networks.com
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