One document matched: draft-thiruvengadam-nsis-mip6-fw-04.txt
Differences from draft-thiruvengadam-nsis-mip6-fw-03.txt
NSIS S. Thiruvengadam
Internet-Draft H. Tschofenig
Expires: December 28, 2006 Siemens
F. Le
CMU
N. Steinleitner
X. Fu
Univ. Goettingen
June 26, 2006
Mobile IPv6 - NSIS Interaction for Firewall traversal
draft-thiruvengadam-nsis-mip6-fw-04.txt
Status of this Memo
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This Internet-Draft will expire on December 28, 2006.
Copyright Notice
Copyright (C) The Internet Society (2006).
Abstract
Most of the firewalls deployed today are Mobile IPv6 unaware.
Widespread Mobile IPv6 deployment is not possible unless Mobile IPv6
messages can pass through these firewalls. One approach is to use a
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signaling protocol to communicate with these firewalls and instruct
them to bypass these Mobile IPv6 messages. The goal of this document
is to describe the interaction between NSIS and Mobile IPv6 for
enabling Mobile IPv6 traversal.
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
3. Mobile node behind a firewall . . . . . . . . . . . . . . . . 5
3.1. Binding updates . . . . . . . . . . . . . . . . . . . . . 5
3.2. Route optimization . . . . . . . . . . . . . . . . . . . . 5
3.3. Bi-directional tunneling . . . . . . . . . . . . . . . . . 7
3.4. Triangular routing . . . . . . . . . . . . . . . . . . . . 7
3.5. Change of Firewalls . . . . . . . . . . . . . . . . . . . 8
3.6. Operations when MN is behind a firewall . . . . . . . . . 9
4. Correspondent Node behind a firewall . . . . . . . . . . . . . 10
4.1. Route Optimization . . . . . . . . . . . . . . . . . . . . 10
4.2. Bi-directional Tunneling . . . . . . . . . . . . . . . . . 12
4.3. Triangular routing . . . . . . . . . . . . . . . . . . . . 13
4.4. Change of Firewalls . . . . . . . . . . . . . . . . . . . 14
4.5. Operations when CN is behind a firewall . . . . . . . . . 14
5. Home Agent behind a firewall . . . . . . . . . . . . . . . . . 16
5.1. Route Optimization . . . . . . . . . . . . . . . . . . . . 16
5.2. Bi-directional tunneling . . . . . . . . . . . . . . . . . 17
5.3. Triangular routing . . . . . . . . . . . . . . . . . . . . 18
5.4. Operations when HA is behind a firewall . . . . . . . . . 18
6. Additional Discussions . . . . . . . . . . . . . . . . . . . . 20
7. Security Considerations . . . . . . . . . . . . . . . . . . . 21
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . . 22
9. References . . . . . . . . . . . . . . . . . . . . . . . . . . 23
9.1. Normative References . . . . . . . . . . . . . . . . . . . 23
9.2. Informative References . . . . . . . . . . . . . . . . . . 23
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . . 24
Intellectual Property and Copyright Statements . . . . . . . . . . 25
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1. Introduction
Route optimization, an integral part of Mobile IPv6 specification
does not work with state of the art firewalls that employ stateful
packet filtering (SPF). This problem is well described in [1]. The
other modes of communication in Mobile IPv6, namely bi-directional
tunneling and triangular routing, also do not work under some
firewall placements. Apart from this, the Mobile IPv6 binding
updates (encapsulated using IPsec ESP) packets also have problems
with firewall traversal. To tackle these issues, one approach is to
utilize a signaling protocol to install some firewall rules for
allowing these Mobile IPv6 messages to pass through. The NSIS NAT/FW
NSLP, as described in [2], allows to establish, maintain and delete
middlebox state (i.e., NAT bindings and Firewall rules), and allow
packets to traverse these boxes. This protocol thus provides a
possible way to address the aforementioned problem. This document
describe the considerations of NSIS NAT/FW NSLP, especially the
involved messages and necessary firewall rules, when firewalls are
encountered in a Mobile IPv6 network. More specifically, the
following basic scenarios are studied individually.
o Mobile Node (MN) behind a firewall;
o Correspondent Node (CN) behind a firewall;
o Home Agent (HA) behind a firewall.
For every scenario, we will discuss how to apply NSIS signaling for
the three routing modes. It has to be noted that a real scenario
could include a combination of some set of these cases. In any case,
we assume that the MN, the CN, the HA and the Firewalls (FWs) are
NSIS aware. Also note that for every NSIS message, the undelying
GIST[5] level provides flow-id information which will be used to
install the firewall policies.
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2. Terminology
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "MAY", and "OPTIONAL" in this
document are to be interpreted as described in [3].
Furthermore, we use the same terminology as in [4], [2], and [6].
Apart from this, we use some abbreviations to describe the flow-id of
the NSIS messages: SA-Source Address, DA-Destination Address, SP-
Source Port, DP-Destination Port and an asterisk is used as wild-
card.
The term 'DS' refers to data sender and the term 'DR' to data
receiver.
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3. Mobile node behind a firewall
In Figure 1, the MN is protected by a firewall that employs stateful
packet filtering (SPF). The external CN and the HA are also shown in
the figure. The MN is in a foreign network and is communicating with
the CN. Here it is assumed that MN has initiated the communication
and hence it has no problems with the SPF.
+----------------+ +----+
| | | HA |
| | +----+
| | Home Agent
| +----+ +----+
| | MN | | FW |
| +----+ +----+
| | +----+
| | | CN |
| | +----+
+----------------+ External CN
Network protected
by a firewall
Figure 1: MN behind the firewall
3.1. Binding updates
IPsec protected Binding Updates cause problems in some deployment
environments, as described in [1]. As a solution, NAT/FW NSLP can be
used to dynamically configure the firewall(s) to allow the IPsec
packets and associated traffic like IKE/IKEv2 packets to traverse,
before sending the binding updates. Therefore, IP Protocol ID 50
should be allowed in the filter policies in order to allow IPsec ESP
and IP Protocol ID 51 to allow IPsec AH. The firewall should also
allow IKE packets (to UDP port 500) to bypass.
For the BU message from MN to HA, the MN installs rules using
CREATE for the flow-id: SA: COA, DA: HA.
3.2. Route optimization
In Figure 2, the message flow for MN behind firewall scenario is
shown (with CN as data sender). Here, all the messages initiated by
the MN will be bypassed. Immediately after moving to a new network,
the MN acquires a new CoA and it performs the Binding Update to the
HA. The HoT message received by the MN is actually a tunneled
message and as it does not belong to the session initiated by the MN,
it will be dropped by the FW. Using REA, the MN initiate NSIS
signaling to the FW and open pinholes for the HoT message.
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For the HoT message from HA to MN, the MN signaling using REA for
the flow-id: SA: HA, DA: CoA.
Once the RRT is successful, the binding update message is sent to the
CN. If the MN wants to continue sending data traffic, then no NSIS
signaling is needed at all for this scenario. However, if the CN
wants to send data traffic, the relevant packet filter rules have to
be installed at the firewall. Hence, the CN has to initiate sending
datta traffic to the MN but this happens after the RRT. The MN has
to perform a Binding Update to the CN, conveying its new CoA.
Therefore, the MN open pinholes using REA to let the data traffic
traverse the firewalls.
For the CREATE message for data traffic from CN to MN, the MN
signaling using REA for the flow-id: SA: CN, DA: CoA, SP: data
application port, DP: data application port.
Network protected
+-------------------------+
| |
| +-----+ +-----+ +----+
| | |Binding Update| | | |
| | |-------->-----+ +--------->----------+ |
| | | | | Binding ACK | |
| | |--------<-----+ +---------<----------+ |
| | MN | REA | FW | | HA |
| | +-------->-----+ | | |
| |(DS) | RESPONSE | | | |
| | +--------<-----+ | | |
| | | | | HoTI | |
| | +-------->-----+ +--------->----------+ |
| | | HoT | | | |
| | +--------<-----+ +---------<----------+ |
| +-----+ +-----+ +----+
| | ^
+-------------------------+ |
v
+----+
| CN |
|(DR)|
+----+
----- = signaling traffic Correspondent node
Figure 2: NSIS signaling for MN behind the firewall
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3.3. Bi-directional tunneling
Consider the scenario where the MN is protected by a SPF. Even
though the MN had earlier initiated a connection for the purpose of
binding update, new filter rules have to be installed to allow the
tunneled data traffic. The message flow is shown in Figure 3.
If the MN is the DS, no signaling is needed at all. Otherwise, the
MN open pinholes to let the data messages traverse, with the help of
REA.
For the CREATE message for data traffic from HA to MN, the MN
signaling using REA for the flow-id: SA: HA, DA: CoA. Note these
data messages for which we do signaling, are IP-in-IP tunneled
messages
Protected network
+-------------------------+
| | Home Agent
| +-----+ +-----+ +----+
| | |Binding update| | | |
| | |-------->-----+ +--------->----------+ |
| | | | | Binding ACK | |
| | |--------<-----+ +---------<----------+ |
| | MN | REA | FW | | HA |
| |(DR) +--------<-----+ | | |
| | | RESPONSE | | | |
| | +-------->-----+ | | |
| | | | | Data traffic | |
| | +*******<******+ +*********<**********+ |
| +-----+ +-----+ +----+
| | *
+-------------------------+ ^
*
+----+
| CN |
|(DS)|
***** = Data traffic +----+
----- = Signaling traffic Correspondent node
Figure 3: NSIS signaling for MN behind the firewall
3.4. Triangular routing
After mobility the MN sends a Binding update message to register its
new CoA. If the CN is the DS, it sends the data to MN through HA.
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If the MN is the data sender, no further signaling is needed as the
session is initiated by the MN. The message flow is shown in
Figure 4.
For the CREATE message for data traffic from HA to MN, the MN
signaling using REA for the flow-id: SA: HA, DA: CoA. Note these
data messages for which we do signaling, are IP-in-IP tunneled
messages.
Network protected
+-------------------------+
| | Home Agent
| +-----+ +-----+ +----+
| | |Binding update| | | |
| | |-------->-----+ +--------->----------+ |
| | | | | Binding ACK | |
| | |--------<-----+ +---------<----------+ |
| | | REA | | | HA |
| | +-------->-----+ | | |
| | | RESPONSE | | | |
| | +--------<-----+ | | |
| | MN | | FW | Tunneled packets | |
| |(DR) +########<#####+ +#########<##########+ |
| | | | | +----+
| | | | | *
| | | | | ^
| | | | | *
| | | | | +----+
| | | | | | CN |
| +-----+ +-----+ |(DS)|
| | +----+
+-------------------------+ Correspondent Node
----- = Signaling traffic
***** = Data traffic
##### = Tunneled data traffic
Figure 4: NSIS signaling for MN behind the firewall
3.5. Change of Firewalls
If the MN roams and attaches to a different firewall, the above-
mentioned routing methods will have problems in traversing the new
firewall. In this case the data sender (where it is MN or the CN or
the HA) should re-signaling to the firewall using NSIS and establish
the policies accordingly (mentioned above according to the routing
methods).
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Since the NAT/FW NSLP rely on a soft-state approach, established
sessions will be automatically be teardown after a specified timeout
value. Thus it is not necessary to delete or teardown a session
after an MN roams to another network, as the protocol will do this by
it own. More discussions about a possible alternative way by tearing
down the established state are given in [7].
3.6. Operations when MN is behind a firewall
MN configure the firewall(s) using CREATE to let following traverse:
o binding update messages (src: CoA, dst: HA) {BU}
o HoTI messages (src: CoA, dst: HA) {RO}
o if uplink firewall, for data traffic from MN (src: MN, dst: *)
MN configures the firewall(s) using REA to let following traverse:
o HoT messages (src: HA dst: CoA) {RO}
o if CN is DS
* for data traffic from HA to MN (src: HA, dst: CoA) {BT}
* for data traffic from HA to MN (src: HA, dst: CoA) {TR}
* for data traffic from CN to MN (src: CN, dst: CoA, SP: data
application port, DP: data application port) {RO}
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4. Correspondent Node behind a firewall
4.1. Route Optimization
In Figure 5, the CN is protected by a firewall that employs stateful
packet filtering (SPF). The external MN and its associated HA are
also shown in the figure. The MN is in its home network and is
communicating with the CN. Here it is assumed that CN has initiated
the communication and hence it has no problems with the SPF.
+----------------+ +----+
| | | HA |
| | +----+
| | Home Agent
| +----+ +----+
| | CN | | FW |
| +----+ +----+
| | +----+
| | | MN |
| | +----+
+----------------+ External Mobile
Network protected Node
by a firewall
Figure 5: CN behind the firewall
The MN moves out of its home network and has to perform the return
routability test (RRT) before sending the binding update to the CN.
It sends a HoTI message through the HA to the CN and expects a HoT
message from the CN along the same path. It also sends a CoTI
message directly to the CN and expects CoT message in the same path
from the CN. The SPF will only allow packets that belong to an
existing session and hence both the packets (HoTI, CoTI) will be
dropped as these packets are Mobile IPv6 packets and these packets
have different header structure. The existing rules at the firewall
might have been installed for some kind of data traffic.
As the RRT can not be executed, the firewalls rules have to be
modified to allow these MIPv6 messages to go through. The MN
initiates the NSIS session by sending a CREATE message to the CN.
When the MN receives both the messages CoT and HoT, it will construct
the binding key and perform binding update to the CN. Note, the
signaling that was aforementioned was only to allow the Mobile IPv6
messages. The message flow for NSIS signaling (with MN as data
sender) is shown in Figure 6. Note, only the message flow between MN
and CN is shown in the diagram.
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For the CREATE message for MIPv6 signaling traffic from MN to CN,
the flow-id will be: SA: CoA, DA: CN. Note: The policy rules that
are to be installed to allow the HoTI and CoTI packets are
different and the NI has to perform signaling twice.
If the CN wants to continue sending data traffic (CN is the DS) to
the new CoA, it can do so without any additional signaling. This is
because the SPF will allow the traffic initiated by the nodes that it
protects. But if the MN wants to continue sending data traffic (MN
is the DS), it has to install filter rules for data traffic. The
prospect of combined signaling (for control and data traffic) could
be useful, but currently the NSIS NAT/FW protocol does not support
installing multiple rules at the same time.
For the CREATE message for data traffic from MN to CN, the flow-id
will be: SA: CoA, DA: CN.
This solution works with the assumption that the firewalls will allow
NSIS messages from external network to bypass with delayed packet
filter state establishment and authorization from the CN. However,
operators might be reluctant to allow NSIS message from external
network as this might lead to DoS attacks. The CN might therefore be
required to authorize the traversal of NSIS signaling message
implicitly to reduce unwanted traffic.
To avoid this, it is also possible to ask the CN to open pinholes in
the firewall on behalf of the MN. But this solution will not work in
some scenarios due to routing asymmetry as explained in [2].
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+-----------------------+ Home Agent
| | +----+
| +-----+ | HA |
| | | +----+
|+----+ | |
|| | | | CREATE +----+
|| +--------<-----+ +---------<----------+ |
|| | RESPONSE | | | |
|| +-------->-----+ FW +--------->----------+ |
|| | | | CoTI | |
|| CN +--------<-----+ +---------<----------+ MN |
|| | CoT | | | |
||(DR)+-------->-----+ +--------->----------+(DS)|
|| | | | Binding update | |
|| +--------<-----+ +---------<----------+ |
|+----+ +-----+ +----+
| | Mobile
+-----------------------+ Node
Network protected
by a firewall
Figure 6: NSIS signaling for CN behind the firewall
4.2. Bi-directional Tunneling
If the CN is protected by a SPF-firewall, there is no need for any
signaling if the CN starts sending data traffic. The CN sends the
data traffic and hence the SPF will store relevant state information
and accepts packets from the reverse direction.
If MN is the DS, then the CN has to initiate the signaling using REA,
in order to configure the firewall to allow the data traffic traverse
from the HA to CN. The message flow is shown in Figure 7.
For the CREATE message for data traffic from HA to CN, the CN
signaling using REA for the flow-id will be: SA: HA, DA: CN.
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Protected network
+-------------------------+
| | Home Agent
| +-----+ +-----+ +----+
| | | | | | |
| | CN | REA | FW | | HA |
| | +-------->-----+ | | |
| |(DR) | RESPONSE | | | |
| | +--------<-----+ | | |
| | | | | Data traffic | |
| | +**************+ +********************+ |
| +-----+ +-----+ +----+
| | #
+-------------------------+ #
+----+
| MN |
|(DS)|
***** = Data traffic (both direction) +----+
----- = signaling traffic Correspondent node
##### = tunneled traffic
Figure 7: NSIS signaling for CN behind the firewall
4.3. Triangular routing
This section considers the scenario shown in Figure 8 where the CN is
protected by a FW that has SPF functionality. If the CN is the DS,
then the data traffic will be bypassed by the firewall. But if the
MN is the DS, the firewall will not allow the data packets from the
MN (packets in the reverse direction) as it does not belong to any
connection that exists already.
Hence, the MN has to initiate signaling by sending the CREATE message
to the CN and the FW will install the policies when it receives the a
sucessful response. Now, the MN is allowed to communicate in the
reverse direction.
For the CREATE message for data traffic from MN to CN, the flow-id
will be: SA: MN, DA: CN, SP: Data application port, DP: Data
application port.
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+-------------------------+
| | Home Agent
| +-----+ +-----+ +----+
| | | | | | HA |
| | | | | +----+
| | CN | | FW |
| |(DR) | | | CREATE +----+
| | +--------<-----+ +---------<----------+ |
| | | RESPONSE | | | MN |
| | +-------->-----+ +--------->----------+(DS)|
| | | | | Data traffic | |
| | +********<*****+ +*********<**********+ |
| +-----+ +-----+ +----+
| | External Mobile
+-------------------------+ Node
Network protected
----- = signaling traffic
***** = Data traffic
Figure 8: NSIS signaling for CN behind the firewall
4.4. Change of Firewalls
If the MN roams and attaches to a network with a different firewall
then the above-mentioned routing methods will have problems in
traversing the new firewall. In this case the data sender (where it
is MN or the CN or the HA) should re-signaling to the firewall using
NSIS and establish the policies accordingly (mentioned above
according to the routing methods).
4.5. Operations when CN is behind a firewall
MN configure the firewall(s) using CREATE to let following traverse:
o HoTI messages (src: CoA, dst: CN) {BU}
o CoTI messages (src: CoA, dst: CN) {BU}
o if MN is DS
* for data traffic from MN to CN (src: CoA, dst: CN) {RO}
* for data traffic from MN to CN (src: CoA, dst: CN, SP: data
application port, DP: data application port) {TR}
CN configure the firewall(s) to let following traverse:
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o HoTI messages (src: HA, dst: CN) {BU}
o if MN is DS for data traffic from HA to CN (src: HA, dst: CN) {BT}
o if uplink firewall, for data traffic from CN (src: CN, dst: MN)
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5. Home Agent behind a firewall
5.1. Route Optimization
The MN, after entering a new network, sends a Binding Update to the
HA. But as it is initiated by the MN, it first has to install some
filter rules in the FW before sending the Binding Update.
The MN-HA Binding Update message is assumed to be IPsec protected.
This might cause problems, as some primitive firewalls do not
recognize IPsec traffic and hence drop the packets because of the
absence of any transport header. Hence UDP encapsulation of IPsec
traffic might be needed to alleviate this problem.
The MN initiates the NSIS signaling to create rules that will allow
the Binding Update messages to bypass. The MN then performs the
Binding Update to the HA.
For the CREATE message for the MIPv6 signaling traffic from MN to
the HA, the flow-id will be: SA: MN, DA: HA, SPIx. (if not UDP
encapsulated).
Note that this section does not consider the usage of the
'Authentication Protocol for Mobile IPv6' protocol [8].
The firewall rules previously installed will not allow the HoTI
message to bypass. Hence, the MN has to install a different set of
rules for these signaling messages, by initiating another signaling
exchange and then it sends the HOTI message to the HA. The HA will
then send the HoTI to CN and obviously this message is allowed as it
is initiated by the HA. The HoT message from the CN to the HA is
also allowed by the SPF as it belongs to the session previously
initiated by the HA. The HoT message from the HA to the MN is also
allowed as it is initiated by the HA. The RRT completes
successfully.
For the CREATE message for the from the MIPv6 signaling traffic MN
to the HA, the flow-id will be: SA: MN, DA: HA.
Detailed message flow (with MN as data sender) is shown in Figure 9.
Note, only the interaction between the HA and the MN is shown in the
figure.
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+------------------------+ +----+
| | | CN |
| | |(DR)|
| | +----+
| |
| +----+ +-----+ +------------------+
| | | | | CREATE | +----+ |
| | +--------<-----+ +---------<------|---<---+ | |
| | | RESPONSE | | | | | |
| | +-------->-----+ +--------->------|--->---+ | |
| | | | | Binding update | | | |
| | +--------<-----+ +---------<------|---<---+ | |
| | HA | | FW | Binding ACK | | MN | |
| | +-------->-----+ +--------->------|--->---+ | |
| | | | | | |(DS)| |
| | | | | CREATE | | | |
| | +--------<-----+ +---------<------|---<---+ | |
| | | RESPONSE | | | | | |
| | +-------->-----+ +--------->------|--->---+ | |
| | | | | HoTI | | | |
| | +--------<-----+ +---------<------|---<---+ | |
| | | | | HoT | | | |
| | +-------->-----+ +--------->------|--->---+ | |
| +----+ +-----+ | +----+ |
| | | |
+------------------------+ +------------------+
HA protected by firewall Visited Network
(Home Network)
Figure 9: NSIS signaling for HA behind the firewall
For the data traffic, there is no additional signaling as the MN
sends data directly to CN and none of these networks (CN network and
MN network) are protected by firewalls. This is applicable for both,
MN and CN, as data senders.
5.2. Bi-directional tunneling
Here, it is necessary that the HA open pinholes for the data traffic
from the CN using REA. The CN is then allowed to send the data
traffic through the FW. After intercepting the packets, the HA
tunnels the packet to the MN. Figure 10 shows the message flow.
For the CREATE message for data traffic from CN to HA, the flow-id
initiated by the HA using REA will be: SA: CN, DA: HoA, SP: Data
application port, DP: Data application port.
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HA Network protected
+-------------------------+
| |
| +-----+ +-----+ +----+
| | | REA | | | |
| | |-------->-----+ | | CN |
| | | RESPONSE | | |(DS)|
| | |--------<-----+ | | |
| | | | | | |
| | HA |********<*****+ FW +*********<**********+ |
| | | | | +----+
| | | | |
| | | | | +----+
| | +########>#####+ +#########>##########+ MN |
| | | | | |(DR)|
| +-----+ +-----+ +----+
| |
+-------------------------+
----- = Signaling traffic
***** = Data traffic
##### = Tunneled data packet
Figure 10: NSIS signaling for HA behind the firewall
5.3. Triangular routing
The HA initiates NSIS signaling to open pinholes in the FW for the
traffic from CN using REA. Then the CN can send the data traffic to
HoA. The message flow is the same as shown in Figure 10.
For the CREATE message for data traffic from CN to HA, the flow-id
initiated by the HA using REA will be: SA: CN, DA: HoA, SP: Data
application port, DP: Data application port.
5.4. Operations when HA is behind a firewall
MN configure the firewall(s) using CREATE to let following traverse:
o binding update messages (src: CoA, dst: HA, SPIx) {BU}
o HoTI messages (src: CoA, dst: HA) {RO}
HA configure the firewall(s) using REA to let following traverse:
o for data traffic from CN to HA (src: CN, dst: HA, SP: data
application port, DP: data application port) {BT}
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o for data traffic from CN to HA (src: CN, dst: HoA, SP: data
application port, DP: data application port) {TR}
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6. Additional Discussions
To support the operations described in this draft, it would be
desireable if the NSIS NAT/FW NSLP has the ability to discover the
presence and the characteristics (e.g., uplink or downlink filter) of
firewalls. This will be useful in several cases. For instance, it
would be desireable if one could detect whether a firewall exists, if
no, then NAT/FW NSLP will be unnecessary. Moreover, it is necessary
to determine where (i.e., in which MIPv6 segment/scenario) is the
firewall. This will be very useful to provide multiple firewall
rules within a single signaling message exchange for multiple traffic
modes (e.g., rules to allow BU and HoTI traverse). Current NAT/FW
NSLP [2] specification does not provide this ability, however, we
believe it would be useful to extend it to be able to discover the
presence and characteristics of firewalls. This desired feature is
already discussed in [9]:
"A client MUST be able to create pinholes and specify the
characteristics of the pinholes to be installed in the firewalls."
To enable the operations defined in this draft, some kind of
interface between Mobile IPv6 and the NAT/FW NSLP is required. This
interface notifies the NSLP about the MIP6 actions, for example the
roaming into a new network and provides the required information
(CoA, HoA, ...). This notification triggeres the required operation.
The protocol uses a firewall detection approach to determine the
current scenario and performs the pinhole creation process necessary
for this case. After creation of the pinholes, MIP6 signaling is
enabled to traverse possible firewalls.
The operation overview will be explained in more detail in future
versions of this draft.
This draft also handles the Triangle Routing case. Further
discussion will cover wheter it is needed to consider triangle
routing at all.
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7. Security Considerations
The NAT/FW NSLP is in itself a very security sensitive service. A
detailed description of possible threats and countermeasures are
described in [2].
More details to authorization and authentication will be provided in
the next version of this draft.
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8. Acknowledgements
Parts of this document are a byproduct of the ENABLE Project,
partially funded by the European Commission under its Sixth Framework
Programme. It is provided "as is" and without any express or implied
warranties, including, without limitation, the implied warranties of
fitness for a particular purpose. The views and conclusions
contained herein are those of the authors and should not be
interpreted as necessarily representing the official policies or
endorsements, either expressed or implied, of the ENABLE Project or
the European Commission.
The authors would like to thank Martin Stiemerling, Cedric Aoun and
Elwyn Davies for the discussions about the NAT/Firewall NSLP.
Additionally, we would like to thank Marcus Brunner and Miquel Martin
for their feedback.
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9. References
9.1. Normative References
[1] Le, F., Faccin, S., Patil, B., and H. Tschofenig, "Mobile IPv6
and Firewalls: Problem Statement", RFC 4487, May 2006.
[2] Stiemerling, M., "NAT/Firewall NSIS Signaling Layer Protocol
(NSLP)", draft-ietf-nsis-nslp-natfw-11 (work in progress),
April 2006.
[3] Bradner, S., "Key words for use in RFCs to Indicate Requirement
Levels", BCP 14, RFC 2119, March 1997.
[4] Johnson, D., Perkins, C., and J. Arkko, "Mobility Support in
IPv6", RFC 3775, June 2004.
9.2. Informative References
[5] Schulzrinne, H. and R. Hancock, "GIST: General Internet
Signaling Transport", draft-ietf-nsis-ntlp-09 (work in
progress), February 2006.
[6] Brunner, M., "Requirements for Signaling Protocols", RFC 3726,
April 2004.
[7] Lee, S., "Applicability Statement of NSIS Protocols in Mobile
Environments",
draft-ietf-nsis-applicability-mobility-signaling-04 (work in
progress), March 2006.
[8] Leung, K., "Authentication Protocol for Mobile IPv6",
draft-ietf-mip6-auth-protocol-07 (work in progress),
September 2005.
[9] Bajko, G., "Requirements for Firewall Configuration Protocol",
draft-bajko-nsis-fw-reqs-04 (work in progress), January 2006.
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Authors' Addresses
Srinath Thiruvengadam
Siemens
Otto-Hahn-Ring 6
Munich, Bavaria 81739
Germany
Email: srinath@mytum.de
Hannes Tschofenig
Siemens
Otto-Hahn-Ring 6
Munich, Bavaria 81739
Germany
Email: Hannes.Tschofenig@siemens.com
Franck Le
Carnegie Mellon University
5000 Forbes Avenue
Pittsburgh, PA 15213
USA
Email: franckle@cmu.edu
Niklas Steinleitner
University of Goettingen
Institute for Informatics
Lotzestr. 16-18
Goettingen 37083
Germany
Email: steinleitner@cs.uni-goettingen.de
Xiaoming Fu
University of Goettingen
Institute for Informatics
Lotzestr. 16-18
Goettingen 37083
Germany
Email: fu@cs.uni-goettingen.de
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