draft-krishnan-mip6-firewall-vendor-00.txt		draft-krishnan-mip6-firewall-vendor-01.txt
	Network Working Group S. Krishnan		Network Working Group S. Krishnan
	Internet-Draft Ericsson		Internet-Draft Ericsson
	Intended status: Informational N. Steinleitner		Intended status: Informational Y. Sheffer
	Expires: May 13, 2008 University of Goettingen		Expires: May 19, 2008 Check Point
	Y. Qiu		N. Steinleitner
	Institute for Infocomm Research		University of Goettingen
	November 10, 2007		November 16, 2007
	Guidelines for firewall vendors regarding MIPv6 traffic		Guidelines for firewall vendors regarding MIPv6 traffic
	draft-krishnan-mip6-firewall-vendor-00		draft-krishnan-mip6-firewall-vendor-01
	Status of this Memo		Status of this Memo
	By submitting this Internet-Draft, each author represents that any		By submitting this Internet-Draft, each author represents that any
	applicable patent or other IPR claims of which he or she is aware		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		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.		aware will be disclosed, in accordance with Section 6 of BCP 79.
	Internet-Drafts are working documents of the Internet Engineering		Internet-Drafts are working documents of the Internet Engineering
	Task Force (IETF), its areas, and its working groups. Note that		Task Force (IETF), its areas, and its working groups. Note that
	skipping to change at page 1, line 37		skipping to change at page 1, line 37
	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."
	The list of current Internet-Drafts can be accessed at		The list of current Internet-Drafts can be accessed at
	http://www.ietf.org/ietf/1id-abstracts.txt.		http://www.ietf.org/ietf/1id-abstracts.txt.
	The list of Internet-Draft Shadow Directories can be accessed at		The list of Internet-Draft Shadow Directories can be accessed at
	http://www.ietf.org/shadow.html.		http://www.ietf.org/shadow.html.
	This Internet-Draft will expire on May 13, 2008.		This Internet-Draft will expire on May 19, 2008.
	Copyright Notice		Copyright Notice
	Copyright (C) The IETF Trust (2007).		Copyright (C) The IETF Trust (2007).
	Abstract		Abstract
	This document presents some recommendations for firewall		This document presents some recommendations for firewall vendors to
	administrators to help them configure their firewalls in a way that		help them implement their firewalls in a way that allows Mobile IPv6
	allows Mobile IPv6 signaling and data messags to pass through. This		signaling and data messages to pass through. This document describes
	document assumes that the firewalls in question include some kind of		how to implement stateful packet filtering capability for MIPv6.
	stateful packet filtering capability.
	Table of Contents		Table of Contents
	1. Requirements notation . . . . . . . . . . . . . . . . . . . . 3		1. Requirements notation . . . . . . . . . . . . . . . . . . . . . 3
	2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 4		2. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
	3. Home Agent behind a firewall . . . . . . . . . . . . . . . . . 5		3. MIPv6 Firewall Primitives . . . . . . . . . . . . . . . . . . . 3
	3.1. Signaling between the MN and the HA . . . . . . . . . . . 5		3.1. Requirements . . . . . . . . . . . . . . . . . . . . . . . 3
	3.2. Route optimization signaling between MN and CN through		3.2. Detecting and parsing the Mobility Header . . . . . . . . . 3
	HA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5		3.3. Parsing Mobility Options . . . . . . . . . . . . . . . . . 3
	3.3. IKEv2 signaling between MN and HA for establishing SAs . . 6		4. Allowing signaling response packets . . . . . . . . . . . . . . 4
	3.4. Data traffic from and to MN passing through the HA . . . . 6		5. Allowing data packets based on signaling . . . . . . . . . . . 5
	4. Correspondent Node behind a firewall . . . . . . . . . . . . . 7		6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 5
	4.1. Route optimization signaling between MN and CN through		7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 6
	HA . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7		8. Security Considerations . . . . . . . . . . . . . . . . . . . . 6
	4.2. Route optimization signaling between MN and CN . . . . . . 7		9. Normative References . . . . . . . . . . . . . . . . . . . . . 6
	4.3. Binding Update from MN to CN . . . . . . . . . . . . . . . 8		Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 7
	4.4. Route Optimization data traffic from MN . . . . . . . . . 8		Intellectual Property and Copyright Statements . . . . . . . . . . 8
	4.5. Bi-directional tunnelled data traffic from the MN to
	the CN through HA . . . . . . . . . . . . . . . . . . . . 8
	5. Mobile Node behind a firewall . . . . . . . . . . . . . . . . 10
	5.1. Signaling between MN and HA . . . . . . . . . . . . . . . 10
	5.2. Signaling between MN and CN . . . . . . . . . . . . . . . 10
	5.3. IKEv2 signaling between MN and HA for establishing SAs . . 11
	5.4. Data traffic from and to the MN . . . . . . . . . . . . . 11
	6. Contributors . . . . . . . . . . . . . . . . . . . . . . . . . 12
	7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 13
	8. Security Considerations . . . . . . . . . . . . . . . . . . . 14
	9. Normative References . . . . . . . . . . . . . . . . . . . . . 15
	Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 16
	Intellectual Property and Copyright Statements . . . . . . . . . . 17
	1. Requirements notation		1. Requirements notation
	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].
	2. Introduction		2. Introduction
	Network elements such as firewalls are an integral aspect of a		Network elements such as firewalls are an integral aspect of a
	majority of IP networks today, given the state of security in the		majority of IP networks today, given the state of security in the
	Internet, threats, and vulnerabilities to data networks. MIPv6		Internet, threats, and vulnerabilities to data networks. MIPv6
	[RFC3775] defines mobility support for IPv6 nodes. Since firewalls		[RFC3775] defines mobility support for IPv6 nodes. Since firewalls
	are not aware of MIPv6 protocol details, they will probably interfere		are not aware of MIPv6 protocol details, they will probably interfere
	with the smooth operation of the protocol. The problems caused by		with the smooth operation of the protocol. The problems caused by
	firewalls to Mobile IPv6 are documented in [RFC4487].		firewalls to Mobile IPv6 are documented in [RFC4487].
	This document presents some recommendations for firewall		This document presents some recommendations for firewall vendors to
	administrators to help them configure their firewalls in a way that		help them implement their firewalls in a way that allows Mobile IPv6
	allows Mobile IPv6 signaling and data messags to pass through. This		signaling and data messags to pass through. This document describes
	document assumes that the firewalls in question include some kind of		how to implement stateful packet filtering capability for MIPv6.
	stateful packet filtering capability.
	3. Home Agent behind a firewall
	This section presents the recommendations for configuring a firewall
	that is protects a home agent. For each type of traffic that needs
	to pass through this firewall, recommendations are presented on how
	to identify that traffic. The following types of traffic are
	considered
	o Signaling between the MN and the HA
	o Route optimization signaling between MN and CN through HA
	o IKEv2 signaling between MN and HA for establishing SAs
	o Data traffic from and to MN passing through the HA
	3.1. Signaling between the MN and the HA		3. MIPv6 Firewall Primitives
	The signaling between the MN and HA is protected using IPSec ESP.		3.1. Requirements
	These messages are encrypted and hence are not inspectable by
	firewalls. So the firewall has to either permit all these messages
	or discard all of them. But if these messages are discarded, Mobile
	IPv6 as specified today will cease to work. In order to permit these
	messages through, the firewall has to detect the messages using the
	following pattern.
	Destination Address: Address of HA		This document assumes that the firewalls are capable of deep packet
	IP payload protocol number: 50 (ESP)		inspection at least until the mobility header. It also assumes that
			the firewalls are capable of creating filters based on arbitrary
			fields based on the contents of a signaling packet.
	This pattern will allow the BU messages from MNs to HA and BA		3.2. Detecting and parsing the Mobility Header
	messages from the HA to the MNs to pass through. It will also allow
	the HoTI and HoT messages (related to route optimization) between the
	MN and the HA to pass through.
	3.2. Route optimization signaling between MN and CN through HA		The Mobility Header is the basic primitive in all MIPv6 signaling
			messages. Thus the firewalls need to be able to recognize the
			presence of the mobility header and be able to parse the contents of
			the Mobility Header. The MH is described in section 6.1 of [RFC3775]
			and the format of the same is scribed in section 6.1.1 of [RFC3775].
			Firewalls need to be able to at least understand the contents of the
			MH Type field that describes the type of signaling message carried.
	Route Optimization allows direct communication of data packets		3.3. Parsing Mobility Options
	between the MN and a CN without tunneling it back through the HA. In
	order for route optimization to work, part of the initial signaling
	has to pass through the HA. The following pattern will allow these
	messages to pass through.
	Destination Address: HoA of MN		The Mobility Header can carry additional information in the form of
	Mobility Header Type: 3		mobility options as described in section 6.2 of [RFC3775]. Some of
			these mobility options need to be understood for proper creation of
			state on the firewalls. Hence firewalls must be able to parse the
			mobility options defined in [RFC3775].
	This pattern allows the HoT message from the CN to the MN's HoA to		4. Allowing signaling response packets
	pass through the firewall. The HoTI message from the MN to the CN
	through the HA usually passes through the firewall without any
	problems. Hence no specific pattern is recommended. If the firewall
	does not have the capability to recognize the mobility header type,
	it needs to at least filter on the IP payload protocol type 135
	(Mobility Header) in order to limit the scope of this filter rule.
	3.3. IKEv2 signaling between MN and HA for establishing SAs		The MIPv6 signalling messages are usually performed as a request-
			response pair. The request message is usually allowed by setting up
			a static firewall rule to allow the traffic to pass through. The
			response message on the other hand can be dynamically allowed if the
			firewall can automatically setup a filter for the response packets
			when the request packet passes through. This is not trivial, but
			fortunately is straightforward. There are 3 message pairs that are
			of importance to MIPv6 signaling. They are the BU/BA, HoTI/HoT and
			CoTI/CoT pairs. When the first message in the pair traverses the
			firewall in one direction, the firewall must setup a filter rule to
			allow the second message through in the other direction.
	The MN and HA exchange IKEv2 signaling in order to establish the		Consider a packet that matches a static rule configured on a firewall
	security associations. The security associations so established will
	later be used for securing the mobility signaling messages. Hence
	these messages need to be permitted to pass through the firewalls.
	The following pattern will detect these messages.
	Destination Address: Address of HA		Destination Address: Address of HA
	Transport Protocol: UDP		Next Header: 50 (ESP)
	Destination UDP Port: 500		Mobility Header Type: 5 (BU)
	3.4. Data traffic from and to MN passing through the HA
	If a CN tries to initiate traffic to an MN, a stateful firewall would
	prevent these connection requests to pass through as there is no
	established state on the firewall. Since MNs do not usually provide
	services, this is not usually a problem. But if this is necessary to
	do, the pattern to look for is
	Destination Address: MN HoA
	Allowing this traffic might allow any kind of traffic, including
	malicious traffic, to pass through unfiltered to the MN. This would
	expose the MN to any type of possibly malicious traffic, resulting in
	a denial of service or exploitation of known security
	vulnerabilities. This practice is NOT RECOMMENDED.
	4. Correspondent Node behind a firewall
	This section presents the recommendations for configuring a firewall
	if a node behind it should be able to act as Mobile IPv6 CN. For
	each type of traffic that needs to pass through this firewall,
	recommendations are presented on how to identify that traffic. The
	following types of traffic are considered
	o Route optimization signaling between MN and CN through HA
	o Route optimization signaling between MN and CN
	o Binding Update from MN to CN
	o Route Optimization data traffic from MN
	o Bi-directional tunnelled data traffic from the MN to the CN
	through HA
	4.1. Route optimization signaling between MN and CN through HA
	Parts of the initial route optimization signaling has to pass through
	the HA, namely the HoTI and the HoT messages. Without assistance,
	the HoTI message from the HA to the CN is not able to traverse the
	firewall. The following pattern will allow these messages to
	traverse.
	Destination Address: CN Address
	Mobility Header Type: 1
	This pinhole allows the HoTI message from the HA to the CN to
	traverse the firewall. The HoT message from the CN to the MN through
	the HA can traverse the firewall without any assistance. Hence no
	pinhole is required.
	4.2. Route optimization signaling between MN and CN
	Route Optimization allows direct communication of data packets
	between the MN and a CN without tunnelling it back through the HA.
	To get route optimization work, the MN has to send a CoTI message
	directly to the CN, which response with a CoT message. However, a
	stateful firewall would prevent the CoTI message to pass through as
	there is no established state on the firewall. The following pinhole
	will allow the CoTI message to traverse.
	Destination Address: CN Address
	Mobility Header Type: 2
	The CoT message from the CN to the MN can traverse the firewall
	without any assistance. Hence no pinhole is required.
	4.3. Binding Update from MN to CN
	After successfully performing the return routability procedure, the
	MN sends the BU to the CN and expects the BA. Since this BU does not
	match any previous installed pinhole rules, an additional pinhole
	with the following format is required.
	Destination Address: CN Address
	Mobility Header Type: 5
	This allows the BU to traverse the firewall and the BA can pass the
	firewall without any assistance. Therefore, the Binding Update
	sequence can be performed successfully.
	4.4. Route Optimization data traffic from MN
	Also the Route Optimization data traffic from MN directly to the CN
	can not traverse the firewall without assistance. But as we have
	configured the firewall to allow the BU message from MN to the CN to
	traverse the firewall, the Route Optimization data traffic is able to
	pass through as it also matches the pinhole installed for the BU.
	Therefore, no additional pinhole rules are required.
	4.5. Bi-directional tunnelled data traffic from the MN to the CN
	through HA
	If a MN tries to initiate traffic to a CN through the HA using bi-
	directional tunnelling, a stateful firewall would prevent these
	connection requests to pass through as there is no established state
	on the firewall. This is usually a problem as CNs often provide
	services. A solution is to static configure the firewall to let this
	traffic pass through. However, this is only an acceptable option if
	it is not necessary to open an all-embracing pinhole, e.g. if the
	destination ports are well-known. In this case, the pinhole has to
	look like
	Destination Address: CN Address
	Destination Port: Application Ports
	If the ports are unknown, it is necessary to install a pinhole with
	only the Destination Address as pattern. Allowing this traffic might
	allow any kind of traffic, including malicious traffic, to traverse
	to the CN. Allowing this traffic might allow any kind of traffic,
	including malicious traffic, to pass through unfiltered to the CN.
	This would expose the CN to any type of possibly malicious traffic,
	resulting in a denial of service or exploitation of known security
	vulnerabilities. This practice is NOT RECOMMENDED
	5. Mobile Node behind a firewall
	This section presents the recommendations for configuring a firewall
	that protects the network a mobile node visiting. For each type of
	traffic that needs to pass through this firewall, recommendations are
	presented on how to identify that traffic. The following types of
	traffic are considered
	o Signaling between MN and HA
	o Route Optimization Signaling between MN and CN
	o IKEv2 signaling between MN and HA for establishing SAs
	o Data traffic from and to MN
	5.1. Signaling between MN and HA
	As described in Section 3.1, the signaling between the MN and HA is		This rule allows a binding update message from a MN to pass through
	protected using IPSec ESP. Currently, a lot of firewalls are		to the HA. Once a packet that matches this rule passes through the
	configured to block the incoming ESP packets. Moreover, from the		firewall, the firewall must setup a dynamic filter for the return
	view of the firewall, both source and destination addresses of these		packet
	messages from/to mobile node are variable. Fortunately, for a
	stateful firewall, if the initial traffic is allowed through the
	firewall, then the return traffic is also allowed. A mobile node is
	always the initiator for the BU. Since MN's CoA is not able to be
	known in advance, the firewall can use following pattern to permit
	these messages through.
	Source Address: Visited subnet prefix		Source Address: Destination Address from Packet
	IP payload protocol number: 50 (ESP)
	This pattern will allow the initial packets (e.g. BU from MNs to HA,		Destination Address: Source Address from Packet
	HoTI, etc.) to pass through the firewall. Then the return packets		Next Header: 50 (ESP)
	(BA from HA to MN, HoT) is also able to pass through accordingly.		Mobility Header Type: 6 (BA)
	5.2. Signaling between MN and CN		This rule ensures that the return BA packet will pass through
			unhindered. The rules can be generalized as summarized in the table
			below.
	Route Optimization allows direct communication of data packets		+---------------------------------+---------------------------------+
	between the MN and a CN without tunneling it back through the HA. It		| Passing packet MH Type | Setup return filter with MH |
	includes 3 pairs of messages: HoTI/HoT, CoTI/CoT and BU/BA. The		| | Type |
	first pair can pass through the firewall using the pattern described		+---------------------------------+---------------------------------+
	in section 5.1. Here we discuss CoTI/CoT and BU/BA messages.		| Mobility Header Type:1(HoTI) | Mobility Header Type:3(HoT) |
	Following pattern permits these messages through the firewall.		| Mobility Header Type:2(CoTI) | Mobility Header Type:4(CoT) |
			| Mobility Header Type:5(BU) | Mobility Header Type:6(BA) |
			+---------------------------------+---------------------------------+
	Source Address: Visited subnet prefix		Table 1: Message Pairs in MIPv6
	IP payload protocol number: 135 (Mobility Header)		Such dynamic rules can be timed out after 420 seconds (the maximum
	This pattern allows the initial messages (CoTI and BU) from the MN to		lifetime of a Binding Cache Entry), unless renewed by new mobility
	the CN pass through the firewall. The return messages (CoT and BA)		messages.
	from the CN to the MN can also passes through the firewall
	accordingly.
	5.3. IKEv2 signaling between MN and HA for establishing SAs		5. Allowing data packets based on signaling
	The MN and HA exchange IKEv2 signaling in order to establish the		Once the MIPv6 signaling completes, the data traffic can begin to
	security associations. The security associations so established will		flow. The traffic filters for the data traffic can be inferred from
	later be used for securing the mobility signaling messages. Due to		the contents of the signaling messages that setup the session. This
	variable source/destination IP addresses and MN always as initiator,		section describes how firewalls can intelligently setup filters for
	the following pattern will let the negotiation pass.		data traffic based on signaling traffic.The following example
			describes how to setup a filter for allowing incoming route optimized
			messages from a CN to an MN after the MN sent a BU message to a CN.
	Source Address: Visited subnet prefix		When the BU message from MN to CN (MH Type 5) traverses through the
	Transport Protocol: UDP		firewall the firewall extracts the home address (HoA) from the Home
	Destination UDP Port: 500		Address Option (section 6.3 of [RFC3775]) of the packet.
	5.4. Data traffic from and to the MN		The firewall adds the following rule in order to let the return
			traffic pass.
	After sending the home binding update, every traffic packet between		Destination Address: Source Address of the packet (MN CoA)
	MN and HA will be encapsulated by ESP. As described in section 5.1,		Source Address: Destination Address of packet (CN)
	the firewall allows theses packets pass through. However, if a CN		Routing Header Type 2 Address: HoA
	tries to initiate traffic to an MN, a stateful firewall would prevent
	these connection requests to pass through as there is no established
	state on the firewall. We may use following steps to establish a
	channel state between MN and CN:
	1. When detecting BU message from MN to CN with protocol number 135		This pattern allows all route optimized traffic coming from the CN to
	and mobility header type 5, the firewall extracts the home		the MN to pass through.
	address from the destination option.
	2. Firewall adds a security rule to its table with following		Additionally, the firewall adds a second rule in order to let the
	pattern.		data traffic from the MN to the CN pass through.
	Destination Address: CoA		Source Address: Source Address of the packet (MN CoA)
	Source Address: CN		Destination Address: Destination Address of packet (CN)
	Routing Header Type 2 Address: HoA		Next Header: IPv6 Destination Options Header(60)
			Home Address Dest. Option: MN HoA
	Thereafter any packets to MN will be filtered by above pattern.		This pattern allows all route optimized traffic coming from the MN to
			the CN to pass through.
	6. Contributors		6. Contributors
	This document is one of the deliverables of the MIPv6 firewall		This document is one of the deliverables of the MIPv6 firewall
	design. The following members of the team were involved in the		design. The following members of the team were involved in the
	creation of this document.		creation of this document.
	Hannes Tschofenig Hannes.Tschofenig@gmx.net		Hannes Tschofenig Hannes.Tschofenig@gmx.net
	Gabor Bajko Gabor.Bajko@nokia.com		Gabor Bajko Gabor.Bajko@nokia.com
	Suresh Krishnan suresh.krishnan@ericsson.com		Suresh Krishnan suresh.krishnan@ericsson.com
	Hesham Soliman solimanhs@gmail.com		Hesham Soliman solimanhs@gmail.com
	Yaron Sheffer yaronf@checkpoint.com		Yaron Sheffer yaronf@checkpoint.com
	Qiu Ying qiuying@i2r.a-star.edu.sg		Qiu Ying qiuying@i2r.a-star.edu.sg
	skipping to change at page 12, line 23		skipping to change at page 6, line 14
	Gabor Bajko Gabor.Bajko@nokia.com		Gabor Bajko Gabor.Bajko@nokia.com
	Suresh Krishnan suresh.krishnan@ericsson.com		Suresh Krishnan suresh.krishnan@ericsson.com
	Hesham Soliman solimanhs@gmail.com		Hesham Soliman solimanhs@gmail.com
	Yaron Sheffer yaronf@checkpoint.com		Yaron Sheffer yaronf@checkpoint.com
	Qiu Ying qiuying@i2r.a-star.edu.sg		Qiu Ying qiuying@i2r.a-star.edu.sg
	Ram Vishnu vishnu@motorola.com
	Niklas Steinleitner steinleitner@cs.uni-goettingen.de		Niklas Steinleitner steinleitner@cs.uni-goettingen.de
	Vijay Devarapalli vijay.devarapalli@AzaireNet.com		Vijay Devarapalli vijay.devarapalli@AzaireNet.com
	7. IANA Considerations		7. IANA Considerations
	This document does not require any IANA action.		This document does not require any IANA action.
	8. Security Considerations		8. Security Considerations
	This document specifies recommendations for firewall administrators		This document specifies recommendations for firewall vendors to allow
	to allow Mobile IPv6 traffic to pass through unhindered. Since some		Mobile IPv6 traffic to pass through unhindered. This document
	of this traffic is encrypted it is not possible for firewalls to		recommends a liberal setting of firewall rules so that all legitimate
	discern whether it is safe or not. This document recommends a		traffic may be allowed to pass. This means that some malicious
	liberal setting so that all legitimate traffic can pass. This means		traffic may be permitted by these rules. These rules may allow the
	that some malicious traffic may be permitted by these rules. These		initiation of Denial of Service attacks against Mobile IPv6 capable
	rules may allow the initiation of Denial of Service attacks against		nodes (the MNs, CNs and the HAs).
	Mobile IPv6 capable nodes (the MNs, CNs and the HAs). Especially the
	rules specified in Section 3.4 and Section 4.5 are broadly defined		One of the main goals of any firewall is to prevent unsolicited
	and hence possess the most potential for abuse. Hence, if these		traffic from entering the network. The proposed solution allows such
	rules are implemented, the firewalls SHOULD be configured to rate-		traffic into the network, albeit with a number of restrictions.
	limit such traffic on a per-destination basis. This would allow the
	firewall to mitigate possible denial of service attacks on the		In a typical enterprise environment, an administrator cannot
	endpoints. Please note that such measures would not mitigate other		distinguish Mobile IPv6 capable nodes from other nodes. In such a
	potential security issues.		situation any node in the protected network may end up receiving
			unsolicited packets from outside the firewall. The risk in this case
			is that such packets could trigger unknown vulnerabilities in any of
			these nodes, causing denial-of-service or worse attacks. This issue
			is compounded in a mobile service provider environment by the risks
			specific to such environments like endpoint battery exhaustion and
			spectrum misuse.
	9. Normative References		9. 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.
	[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support		[RFC3775] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support
	in IPv6", RFC 3775, June 2004.		in IPv6", RFC 3775, June 2004.
	[RFC4487] Le, F., Faccin, S., Patil, B., and H. Tschofenig, "Mobile		[RFC4487] Le, F., Faccin, S., Patil, B., and H. Tschofenig, "Mobile
	skipping to change at page 16, line 16		skipping to change at page 7, line 24
	Suresh Krishnan		Suresh Krishnan
	Ericsson		Ericsson
	8400 Decarie Blvd.		8400 Decarie Blvd.
	Town of Mount Royal, QC		Town of Mount Royal, QC
	Canada		Canada
	Phone: +1 514 345 7900 x42871		Phone: +1 514 345 7900 x42871
	Email: suresh.krishnan@ericsson.com		Email: suresh.krishnan@ericsson.com
			Yaron Sheffer
			Check Point
			5 Hasolelim St.
			Tel Aviv 67897
			Israel
			Email: yaronf@checkpoint.com
	Niklas Steinleitner		Niklas Steinleitner
	University of Goettingen		University of Goettingen
	Lotzestr. 16-18		Lotzestr. 16-18
	Goettingen		Goettingen
	Germany		Germany
	Email: steinleitner@cs.uni-goettingen.de		Email: steinleitner@cs.uni-goettingen.de
	Ying Qiu
	Institute for Infocomm Research
	21 Heng Mui Keng Terrace
	Singapore
	Phone: +65-6874-6742
	Email: qiuying@i2r.a-star.edu.sg
	Full Copyright Statement		Full Copyright Statement
	Copyright (C) The IETF Trust (2007).		Copyright (C) The IETF Trust (2007).
	This document is subject to the rights, licenses and restrictions		This document is subject to the rights, licenses and restrictions
	contained in BCP 78, and except as set forth therein, the authors		contained in BCP 78, and except as set forth therein, the authors
	retain all their rights.		retain all their rights.
	This document and the information contained herein are provided on an		This document and the information contained herein are provided on an
	"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS		"AS IS" basis and THE CONTRIBUTOR, THE ORGANIZATION HE/SHE REPRESENTS
End of changes. 37 change blocks.
	314 lines changed or deleted		142 lines changed or added
This html diff was produced by rfcdiff 1.34. The latest version is available from http://tools.ietf.org/tools/rfcdiff/