Network Working Group J. Wu
Internet-Draft G. Ren
Intended status: Experimental J. Bi
Expires: January 14, 2009 X. Li
CERNET
M. Williams
Juniper Networks
July 13, 2008
A Solution For Source Address Validation in Local Subnet Environment
draft-wu-sava-solution-firsthop-eap-01
Status of this Memo
By submitting this Internet-Draft, each author represents that any
applicable patent or other IPR claims of which he or she is aware
have been or will be disclosed, and any of which he or she becomes
aware will be disclosed, in accordance with Section 6 of BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF), its areas, and its working groups. Note that
other groups may also distribute working documents as Internet-
Drafts.
Internet-Drafts are draft documents valid for a maximum of six 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
http://www.ietf.org/ietf/1id-abstracts.txt.
The list of Internet-Draft Shadow Directories can be accessed at
http://www.ietf.org/shadow.html.
This Internet-Draft will expire on January 14, 2009.
Abstract
This document describes a solution for preventing source address
spoofing in the local subnet of the Internet. The main idea of the
solution is to get a dynamic binding between IP address and access
switch port.
Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
Wu, et al. Expires January 14, 2009 [Page 1]
Internet-Draft Abbreviated-Title July 2008
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in RFC 2119 [RFC2119].
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Local Subnet Source Address Validation . . . . . . . . . . . . 3
2.1. Problem Description . . . . . . . . . . . . . . . . . . . . 3
2.2. Focus of the Solution . . . . . . . . . . . . . . . . . . . 4
3. An IP Address-Switch Port Binding Solution . . . . . . . . . . 4
3.1. System Architecture . . . . . . . . . . . . . . . . . . . . 4
3.2. Key Mechanisms . . . . . . . . . . . . . . . . . . . . . . 6
3.3. Discussion of Control Protocol . . . . . . . . . . . . . . 6
4. CNGI-CERNET2 Test Experience . . . . . . . . . . . . . . . . . 6
5. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 7
6. Security Considerations . . . . . . . . . . . . . . . . . . . . 7
7. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 7
8. References . . . . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Normative References . . . . . . . . . . . . . . . . . . . 7
8.2. Informative References . . . . . . . . . . . . . . . . . . 7
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
Intellectual Property and Copyright Statements . . . . . . . . . . 9
Wu, et al. Expires January 14, 2009 [Page 2]
Internet-Draft Abbreviated-Title July 2008
1. Introduction
The problem of source address validation is decomposed hierarchically
into three levels of granularity in [I-D.wu-sava-framework] for
discussion: local subnet source validation, intra-AS source
validation, and inter-AS source validation.
The local subnet source validation is the crucial level in the
hierarchy when it comes to achieving "strict-validated"SAVA status,
which means the packet can be traced back to an individual host that
is authorized to emit packets with that source address. An IP
address-switch port binding solution is proposed in this document.
There have been many efforts in the research and engineering
community to design mechanisms related to source address validation
in local subnet environment. IP Source Guard and DHCP Lease Query
are related solution examples.
It should be stressed that at this early stage, the solutions
proposed in this solution document are not intended to pre-empt other
work carried out by the IETF in the solution space. Furthermore, it
is envisaged that more than one solution could be devised and
deployed for each of the proposed solution elements required under
the framework, in keeping with the requirement for a loosely-coupled
architecture and, as far as possible, a plug-and-play framework.
The intention of this document is to provide some potential solution
ideas which have been implemented on the testbed described
in[I-D.wu-sava-testbed-experience]. Some other procedures that could
be used as solution elements in the local subnet source validation
have been devised and one is introduced and discussed in
[I-D.baker-sava-cisco-ip-source-guard].
2. Local Subnet Source Address Validation
2.1. Problem Description
The deployment of BCP38 typically requires that the source address of
a packet entering the provider network belong to a prefix that is
allocated to or has transit through the attached access network. If
there is no special consideration, one host can still spoof source
address by sending packet with the "legal" IP address of another host
with same IP prefix. The goal of the Local Subnet source address
validation is to solve the source address spoofing problem in these
scenarios. That is, to achieve "strict-validated" SAVA validation
status, which means the packet can be traced back to an individual
host that is authorized to emit packets with that source address.
Wu, et al. Expires January 14, 2009 [Page 3]
Internet-Draft Abbreviated-Title July 2008
See detail in [I-D.wu-sava-framework].
2.2. Focus of the Solution
There are several different local subnet scenarios: enterprise
networks with switches, home broadband access, access from a wireless
mobile device etc. The focus of the solution described in this
document is enterprise networks with switches.The source address may
be assigned to the host in a static way or a dynamic way.
The solution tested in the SAVA testbed takes the strongest
requirement for validation in the local subnet. That is, any IPv6
address should have a unique association with an entity that is
specifically authorised to use that IPv6 address. The SAVA testbed
has implemented a solution for IPv6 only. The principles can be
extended to IPv4 without difficulty.
3. An IP Address-Switch Port Binding Solution
3.1. System Architecture
The main idea of the solution described in this document is based on
creating a dynamic binding between a switch port and valid source IP
address, or a binding between MAC address, source IP address and
switch port.
There are four main modules of the system: Source Address Request
Client (SARC) on the host, Source Address Validation Proxy (SAVP) on
the switch, Source Address Management Server (SAMS) and Interface to
the Authentication Server (IAS). The system architecture is shown in
Figure 1.
Wu, et al. Expires January 14, 2009 [Page 4]
Internet-Draft Abbreviated-Title July 2008
---------
| IAS |
------|-
|
----------------
| SERVER |
| ------- |
| | SAMS | |
| -------- |
-----------------
|
|
----------------
| SWITCH |
| ------- |
| | SAVP | |
| -------- |
-----------------
|
|
----------------
| END HOST |
| ------- |
| | SARC | |
| -------- |
-----------------
Key: SARC == Source Address Request Client , SAVP == Source Address
Validation Proxy, SAMS== Source Address Management Server, IAS==
Interface to the Authentication Server
Figure 1: System Architecture
o SARC sends an IP address request to the SAMS.
o SAVP relays the IP address request from SARC to SAMS and the IP
addess response from SAMS to SARC. It maintain a binding table
between switch port and source IP address.
o SAMS receives the request from SARC and generates an address
response to SARC based on the address allocation and management
policy of the local subnet. It can contact to the authentication
server for identification and access control via IAS. The
allocation history of the address is stored in SAMS for future
traceback.
o IAS is the interface between the SAMS and authentication server.
In many cases, the allocation and binding of IP addresses is
performed after a process of identity discovery and application of
Wu, et al. Expires January 14, 2009 [Page 5]
Internet-Draft Abbreviated-Title July 2008
access control policy.
3.2. Key Mechanisms
The solution's principle steps are as follows:
1. The SARC on the end host sends an IP address request. The SAVP
on the switch relays this request to the SAMS. If the address
has been predetermined by the end host, it still needs to put it
in the request datagram for acceptance from SAMS.
2. SAMS receives the IP address request, and generates an address
response to SARC based on the address allocation and management
policy of the local subnet. The allocation of the IP address is
stored in the history database of SAMS for traceback. If the
allocation and binding of IP address is performed process of
identity discovery and application of access control policy, do
the identification via IAS. If authorization is successful, send
the IP address response to the SARC.
3. The SAVP on the access switch receives the response, and binds
the IP address with the switch port on the binding table. In
addition, it forwards the issued address to SARC on the end host.
4. The access switch begins to filter packets sent from the end
host. Packets which do not conform to the tuple (IP address,
Switch Port) are discarded.
3.3. Discussion of Control Protocol
The control protocol for generating binding rules of IP address and
switch port can be an extension of DHCP, or a new protocol. The
allocation and binding of IP address can also performed after a
process of access control and identification. For the implementation
in CNGI-CERNET2 testbed, The communication between SARC and SAVP is
an extension of EAP, and the communication between SAVP and SAMS is
an extension of Radius.
4. CNGI-CERNET2 Test Experience
The solutions outlined above have been implemented on the testbed of
CNGI-CERNET2. An extension of EAP is used for the communication
between SARC and SAVP, and an extension of Radius is used for the
communication between SAVP and SAMS. Successful testing of the
solution has been carried out. A more detailed discussion is
described in [I-D.wu-sava-testbed-experience].
Wu, et al. Expires January 14, 2009 [Page 6]
Internet-Draft Abbreviated-Title July 2008
5. IANA Considerations
This document makes no request of IANA.
6. Security Considerations
7. Acknowledgements
8. References
8.1. Normative References
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119, March 1997.
8.2. Informative References
[I-D.baker-sava-cisco-ip-source-guard]
Baker, F., "Cisco IP Version 4 Source Guard",
draft-baker-sava-cisco-ip-source-guard-00 (work in
progress), November 2007.
[I-D.wu-sava-framework]
Wu, J., "Source Address Validation Architecture (SAVA)
Framework", draft-wu-sava-framework-01 (work in progress),
July 2007.
[I-D.wu-sava-problem-statement]
Wu, J., Bonica, R., Bi, J., Li, X., Ren, G., and M.
Williams, ""Source Address Validation Architecture (SAVA)
Problem Statement", draft-wu-sava-problem-statement-00
(Work in Progress)", February 2007.
[I-D.wu-sava-testbed-experience]
Wu, J., Bi, J., Li, X., Ren, G., Xu, K., and M. Williams,
"SAVA Testbed and Experiences to Date",
draft-wu-sava-testbed-experience-06 (work in progress),
May 2008.
Wu, et al. Expires January 14, 2009 [Page 7]
Internet-Draft Abbreviated-Title July 2008
Authors' Addresses
Jianping Wu
CERNET
Network Center, Tsinghua University
Beijing 100084
China
Email: jianping@cernet.edu.cn
Gang Ren
CERNET
Network Center, Tsinghua University
Beijing 100084
China
Email: rg03@mails.tsinghua.edu.cn
Jun Bi
CERNET
Network Center, Tsinghua University
Beijing 100084
China
Email: junbi@cernet.edu.cn
Xing Li
CERNET
Network Center, Tsinghua University
Beijing 100084
China
Email: xing@cernet.edu.cn
Mark I. Williams
Juniper Networks
Suite 1508, W3 Tower, Oriental Plaza, 1 East Chang'An Ave
Dong Cheng District, Beijing 100738
China
Email: miw@juniper.net
Wu, et al. Expires January 14, 2009 [Page 8]
Internet-Draft Abbreviated-Title July 2008
Full Copyright Statement
Copyright (C) The IETF Trust (2008).
This document is subject to the rights, licenses and restrictions
contained in BCP 78, and except as set forth therein, the authors
retain all their rights.
This document and the information contained herein are provided on an
"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
OR IS SPONSORED BY (IF ANY), THE INTERNET SOCIETY, THE IETF TRUST AND
THE INTERNET ENGINEERING TASK FORCE DISCLAIM ALL WARRANTIES, EXPRESS
OR IMPLIED, INCLUDING BUT NOT LIMITED TO ANY WARRANTY THAT THE USE OF
THE INFORMATION HEREIN WILL NOT INFRINGE ANY RIGHTS OR ANY IMPLIED
WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE.
Intellectual Property
The IETF takes no position regarding the validity or scope of any
Intellectual Property Rights or other rights that might be claimed to
pertain to the implementation or use of the technology described in
this document or the extent to which any license under such rights
might or might not be available; nor does it represent that it has
made any independent effort to identify any such rights. Information
on the procedures with respect to rights in RFC documents can be
found in BCP 78 and BCP 79.
Copies of IPR disclosures made to the IETF Secretariat and any
assurances of licenses to be made available, or the result of an
attempt made to obtain a general license or permission for the use of
such proprietary rights by implementers or users of this
specification can be obtained from the IETF on-line IPR repository at
http://www.ietf.org/ipr.
The IETF invites any interested party to bring to its attention any
copyrights, patents or patent applications, or other proprietary
rights that may cover technology that may be required to implement
this standard. Please address the information to the IETF at
ietf-ipr@ietf.org.
Wu, et al. Expires January 14, 2009 [Page 9]