Internet DRAFT - draft-boucadair-dots-multihoming
draft-boucadair-dots-multihoming
Network Working Group M. Boucadair
Internet-Draft Orange
Intended status: Standards Track T. Reddy
Expires: April 10, 2019 McAfee
October 7, 2018
Multi-homing Deployment Considerations for Distributed-Denial-of-Service
Open Threat Signaling (DOTS)
draft-boucadair-dots-multihoming-04
Abstract
This document discusses multi-homing considerations for Distributed-
Denial-of-Service Open Threat Signaling (DOTS). The goal is to
provide a set of guidance for DOTS clients/gateways when multihomed.
Status of This Memo
This Internet-Draft is submitted in full conformance with the
provisions of BCP 78 and BCP 79.
Internet-Drafts are working documents of the Internet Engineering
Task Force (IETF). Note that other groups may also distribute
working documents as Internet-Drafts. The list of current Internet-
Drafts is at https://datatracker.ietf.org/drafts/current/.
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."
This Internet-Draft will expire on April 10, 2019.
Copyright Notice
Copyright (c) 2018 IETF Trust and the persons identified as the
document authors. All rights reserved.
This document is subject to BCP 78 and the IETF Trust's Legal
Provisions Relating to IETF Documents
(https://trustee.ietf.org/license-info) in effect on the date of
publication of this document. Please review these documents
carefully, as they describe your rights and restrictions with respect
to this document. Code Components extracted from this document must
include Simplified BSD License text as described in Section 4.e of
the Trust Legal Provisions and are provided without warranty as
described in the Simplified BSD License.
Boucadair & Reddy Expires April 10, 2019 [Page 1]
Internet-Draft DOTS Multihoming October 2018
Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . 2
2. Requirements Language . . . . . . . . . . . . . . . . . . . . 4
3. Terminology . . . . . . . . . . . . . . . . . . . . . . . . . 4
4. Multi-Homing Scenarios . . . . . . . . . . . . . . . . . . . 4
4.1. Residential CPE . . . . . . . . . . . . . . . . . . . . . 4
4.2. Multi-homed Enterprise: Single CPE, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 5
4.3. Multi-homed Enterprise: Multiple CPEs, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 6
4.4. Multi-homed Enterprise with the Same ISP . . . . . . . . 7
5. DOTS Deployment Considerations . . . . . . . . . . . . . . . 7
5.1. Residential CPE . . . . . . . . . . . . . . . . . . . . . 7
5.2. Multi-homed Enterprise: Single CPE, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 8
5.3. Multi-homed Enterprise: Multiple CPEs, Multiple Upstream
ISPs . . . . . . . . . . . . . . . . . . . . . . . . . . 10
5.4. Multi-homed Enterprise: Single ISP . . . . . . . . . . . 11
6. Security Considerations . . . . . . . . . . . . . . . . . . . 12
7. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 12
8. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 12
9. References . . . . . . . . . . . . . . . . . . . . . . . . . 12
9.1. Normative References . . . . . . . . . . . . . . . . . . 12
9.2. Informative References . . . . . . . . . . . . . . . . . 13
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 14
1. Introduction
In many deployments, it may not be possible for a network to
determine the cause for a distributed Denial-of-Service (DoS) attack
[RFC4732], but instead just realize that some resources seem to be
under attack. To fill that gap, the IETF is specifying an
architecture, called DDoS Open Threat Signaling (DOTS)
[I-D.ietf-dots-architecture], in which a DOTS client can inform a
DOTS server that the network is under a potential attack and that
appropriate mitigation actions are required. Indeed, because the
lack of a common method to coordinate a real-time response among
involved actors and network domains inhibits the effectiveness of
DDoS attack mitigation, DOTS protocol is meant to carry requests for
DDoS attack mitigation, thereby reducing the impact of an attack and
leading to more efficient defensive actions.
[I-D.ietf-dots-use-cases] identifies a set of scenarios for DOTS;
almost all these scenarios involve a CPE.
The basic high-level DOTS architecture is illustrated in Figure 1
([I-D.ietf-dots-architecture]):
Boucadair & Reddy Expires April 10, 2019 [Page 2]
Internet-Draft DOTS Multihoming October 2018
+-----------+ +-------------+
| Mitigator | ~~~~~~~~~~ | DOTS Server |
+-----------+ +-------------+
|
|
|
+---------------+ +-------------+
| Attack Target | ~~~~~~ | DOTS Client |
+---------------+ +-------------+
Figure 1: Basic DOTS Architecture
[I-D.ietf-dots-architecture] specifies that the DOTS client may be
provided with a list of DOTS servers; each associated with one or
more IP addresses. These addresses may or may not be of the same
address family. The DOTS client establishes one or more DOTS
signaling sessions by connecting to the provided DOTS server(s)
addresses.
DOTS may be deployed within networks that are connected to one single
upstream provider. It can also be enabled within networks that are
multi-homed. The reader may refer to [RFC3582] for an overview of
multi-homing goals and motivations. This document discusses DOTS
multi-homing considerations. Specifically, the document aims to:
1. Complete the base DOTS architecture with multi-homing specifics.
Those specifics need to be taking into account because:
* Send a DOTS mitigation request to an arbitrary DOTS server
won't help mitigating a DDoS attack.
* Blindly forking all DOTS mitigation requests among all
available DOTS servers is suboptimal.
* Sequentially contacting DOTS servers may increase the delay
before a mitigation plan is enforced.
2. Identify DOTS deployment schemes in a multi-homing context, where
DOTS service can be offered by all or a subset of upstream
providers.
3. Sketch guidelines and recommendations for placing DOTS requests
in multi-homed networks, e.g.,:
* Select the appropriate DOTS server(s).
* Identify cases where anycast is not recommended.
Boucadair & Reddy Expires April 10, 2019 [Page 3]
Internet-Draft DOTS Multihoming October 2018
To that aim, this document adopts the following methodology:
o Identify and extract viable deployment candidates from
[I-D.ietf-dots-use-cases].
o Augment the description with multi-homing technicalities, e.g.,
* One vs. multiple upstream network providers
* One vs. multiple interconnect routers
* Provider-Independent (PI) vs. Provider-Aggregatable (PA)
o Describe the recommended behavior of DOTS clients and gateways for
each case.
Multi-homed DOTS agents are assumed to make use of the protocols
defined in [I-D.ietf-dots-signal-channel] and
[I-D.ietf-dots-data-channel]; no specific extension is required to
the base DOTS protocols for deploying DOTS in a multihomed context.
2. Requirements Language
The key words "MUST", "MUST NOT", "REQUIRED", "SHALL", "SHALL NOT",
"SHOULD", "SHOULD NOT", "RECOMMENDED", "NOT RECOMMENDED", "MAY", and
"OPTIONAL" in this document are to be interpreted as described in BCP
14 [RFC2119][RFC8174] when, and only when, they appear in all
capitals, as shown here.
3. Terminology
This document makes use of the terms defined in
[I-D.ietf-dots-architecture] and [RFC4116].
IP refers to both IPv4 and IPv6.
4. Multi-Homing Scenarios
This section briefly describes some multi-homing scenarios that are
relevant to DOTS. In the following sub-sections, only the
connections of border routers are shown; internal network topologies
are not elaborated hereafter.
4.1. Residential CPE
The scenario shown in Figure 2 is characterized as follows:
Boucadair & Reddy Expires April 10, 2019 [Page 4]
Internet-Draft DOTS Multihoming October 2018
o The home network is connected to the Internet using one single CPE
(Customer Premises Equipment).
o The CPE is connected to multiple provisioning domains (i.e. both
fixed and mobile networks). Provisioning domain (PvD) is
explained in [RFC7556].
o Each of these provisioning domains assign IP addresses/prefixes to
the CPE. These addresses/prefixes are said to be Provider-
Aggregatable (PA).
o The CPE is provided by each of these provisioning domains with
additional configuration information such as a list of DNS
servers, DNS suffixes associated with the network, default gateway
address, and DOTS server's name
[I-D.boucadair-dots-server-discovery].
o Because of ingress filtering, packets forwarded by the CPE to a
given provisioning domain must be send with a source IP address
that was assigned by that network [RFC8043].
+-------+ +-------+
|Fixed | |Mobile |
|Network| |Network|
+---+---+ +---+---+
| | Service Providers
............|....................|.......................
+---------++---------+ Home Network
||
+--++-+
| CPE |
+-----+
... (Internal Network)
Figure 2: Typical Multi-homed Residential CPE
4.2. Multi-homed Enterprise: Single CPE, Multiple Upstream ISPs
The scenario shown in Figure 3 is characterized as follows:
o The enterprise network is connected to the Internet using one
single router.
o That router is connected to multiple provisioning domains (i.e.
managed by distinct administrative entities).
Boucadair & Reddy Expires April 10, 2019 [Page 5]
Internet-Draft DOTS Multihoming October 2018
Unlike the previous scenario, two sub-cases can be considered for an
enterprise network with regards to assigned addresses:
1. Provider Independent (PI) addresses: The enterprise is the owner
of the IP addresses/prefixes; the same address/prefix is then
used for communication placed using any of the provisioning
domains.
2. PA addresses/prefixes: each of provisioning domains assigns IP
addresses/prefixes to the enterprise network.
+------+ +------+
| ISP1 | | ISP2 |
+---+--+ +--+---+
| | Service Providers
............|....................|.......................
+---------++---------+ Enterprise Network
||
+--++-+
| rtr |
+-----+
... (Internal Network)
Figure 3: Multi-homed Enterprise Network (Single CPE connected to
Multiple Networks)
4.3. Multi-homed Enterprise: Multiple CPEs, Multiple Upstream ISPs
This scenario is similar to the one in Section 4.2; the main
difference is that dedicated routers are used to connect to each
provisioning domain.
+------+ +------+
| ISP1 | | ISP2 |
+---+--+ +--+---+
| | Service Providers
......................|..........|.......................
| | Enterprise Network
+---+--+ +--+---+
| rtr1 | | rtr2 |
+------+ +------+
... (Internal Network)
Figure 4: Multi-homed Enterprise Network (Multiple CPEs, Multiple
ISPs)
Boucadair & Reddy Expires April 10, 2019 [Page 6]
Internet-Draft DOTS Multihoming October 2018
4.4. Multi-homed Enterprise with the Same ISP
This scenario is a variant of Section 4.2 and Section 4.3 in which
multi-homing is provided by the same ISP (i.e., same provisioning
domain).
5. DOTS Deployment Considerations
Table 1 provides some sample (non-exhaustive) deployment schemes to
illustrate how DOTS agents may be deployed for each of the scenarios
introduced in Section 4.
+---------------------------+-------------------------+-------------+
| Scenario | DOTS client | DOTS |
| | | gateway |
+---------------------------+-------------------------+-------------+
| Residential CPE | CPE | N/A |
+---------------------------+-------------------------+-------------+
| Single CPE, Multiple | internal hosts or CPE | CPE |
| provisioning domains | | |
+---------------------------+-------------------------+-------------+
| Multiple CPEs, Multiple | internal hosts or all | CPEs (rtr1 |
| provisioning domains | CPEs (rtr1 and rtr2) | and rtr2) |
+---------------------------+-------------------------+-------------+
| Multi-homed enterprise, | internal hosts or all | CPEs (rtr1 |
| Single provisioning | CPEs (rtr1 and rtr2) | and rtr2) |
| domain | | |
+---------------------------+-------------------------+-------------+
Table 1: Sample Deployment Cases
These deployment schemes are further discussed in the following sub-
sections.
5.1. Residential CPE
Figure 5 depicts DOTS signaling sessions that are required to be
established between a DOTS client (C) and DOTS servers (S1, S2) in
the context of the scenario described in Section 4.1.
The DOTS client MUST resolve the DOTS server's name provided by a
provisioning domain ([I-D.boucadair-dots-server-discovery]) using the
DNS servers learned from the same provisioning domain. The DOTS
client MUST use the source address selection algorithm defined in
[RFC6724] to select the candidate source addresses to contact each of
these DOTS servers. DOTS signaling sessions must be established and
maintained with each of the DOTS servers because the mitigation scope
of these servers is restricted. The DOTS client SHOULD use the
Boucadair & Reddy Expires April 10, 2019 [Page 7]
Internet-Draft DOTS Multihoming October 2018
certificate provisioned by a provisioning domain to authenticate
itself to the DOTS server provided by the same provisioning domain.
When conveying a mitigation request to protect the attack target(s),
the DOTS client among the DOTS servers available MUST select a DOTS
server whose network has assigned the prefixes from which target
prefixes and target IP addresses are derived. For example,
mitigation request to protect target resources bound to a PA IP
address/prefix cannot be honored by an provisioning domain other than
the one that owns those addresses/prefixes. Consequently, Typically,
if a CPE detects a DDoS attack on all its network attachments, it
must contact both DOTS servers for mitigation. Nevertheless, if the
DDoS attack is received from one single network, then only the DOTS
server of that network must be contacted.
The DOTS client MUST be able to associate a DOTS server with each
provisioning domain. For example, if the DOTS client is provisioned
with S1 using DHCP when attaching to a first network and with S2
using Protocol Configuration Option (PCO) when attaching to a second
network, the DOTS client must record the interface from which a DOTS
server was provisioned. DOTS signaling session to a given DOTS
server must be established using the interface from which the DOTS
server was provisioned.
+--+
-----------|S1|
/ +--+
/
/
+---+/
| C |
+---+\
\
\
\ +--+
-----------|S2|
+--+
Figure 5: DOTS associations for a multihomed residential CPE
5.2. Multi-homed Enterprise: Single CPE, Multiple Upstream ISPs
Figure 6 illustrates a first set of DOTS associations that can be
established with a DOTS gateway is enabled in the context of the
scenario described in Section 4.2. This deployment is characterized
as follows:
o One of more DOTS clients are enabled in hosts located in the
internal network.
Boucadair & Reddy Expires April 10, 2019 [Page 8]
Internet-Draft DOTS Multihoming October 2018
o A DOTS getaway is enabled to aggregate/relay the requests to
upstream DOTS servers.
When PA addresses/prefixes are in used, the same considerations
discussed in Section 5.1 are to be followed by the DOTS gateway to
contact its DOTS server(s). The DOTS gateways can be reachable from
DOTS client using a unicast or anycast address.
Nevertheless, when PI addresses/prefixes are assigned, the DOTS
gateway MUST sent the same request to all its DOTS servers.
+--+
-----------|S1|
+---+ / +--+
| C1|----+ /
+---+ | /
+---+ +-+-+/
| C3|------| G |
+---+ +-+-+\
+---+ | \
| C2|----+ \
+---+ \ +--+
-----------|S2|
+--+
Figure 6: Multiple DOTS Clients, Single DOTS Gateway, Multiple DOTS
Servers
An alternate deployment model is depicted in Figure 7. This
deployment assumes that:
o One of more DOTS clients are enabled in hosts located in the
internal network. These DOTS client may use
[I-D.boucadair-dots-server-discovery] to discover its DOTS
server(s).
o These DOTS clients communicate directly with upstream DOTS
servers.
If PI addresses/prefixes are in use, the DOTS client can send the
mitigation request for all its PI addresses/prefixes to any one of
the DOTS servers. The use of anycast addresses is NOT RECOMMENDED.
If PA addresses/prefxies are used, the same considerations discussed
in Section 5.1 are to be followed by the DOTS clients. Because DOTS
clients are not located on the CPE and multiple addreses/prefixes may
not be assigned to the DOTS client (IPv4 context, typically), some
complications arise to steer the traffic to the appropriate DOTS
Boucadair & Reddy Expires April 10, 2019 [Page 9]
Internet-Draft DOTS Multihoming October 2018
server using the appropriate source IP address. These complications
discussed in [RFC4116] are not specific to DOTS .
+--+
+--------|C1|--------+
| +--+ |
+--+ +--+ +--+
|S2|------|C3|------|S1|
+--+ +--+ +--+
| +--+ |
+--------|C2|--------+
+--+
Figure 7: Multiple DOTS Clients, Multiple DOTS Servers
Another deployment approach is to enable many DOTS clients; each of
them responsible to handle communication with a specific DOTS server
(see Figure 8). Each DOTS client is provided with policies (e.g.,
prefix filter) that will trigger DOTS communications with the DOTS
servers. The CPE MUST select the appropriate source IP address when
forwarding DOTS messages received from an internal DOTS client. If
anycast addresses are used to reach DOTS servers, the CPE may not be
able to select the appropriate provisioning domain to which the
mitigation request should be forwarded. As a consequence, the
request may not be forwarded to the appropriate DOTS server.
+--+
+--------|C1|
| +--+
+--+ +--+ +--+
|S2| |C2|------|S1|
+--+ +--+ +--+
Figure 8: Single Homed DOTS Clients
5.3. Multi-homed Enterprise: Multiple CPEs, Multiple Upstream ISPs
The deployments depicted in Figure 7 and Figure 8 apply also for the
scenario described in Section 4.3. One specific problem for this
scenario is to select the appropriate exit router when contacting a
given DOTS server.
An alternative deployment scheme is shown in Figure 9:
o DOTS clients are enabled in hosts located in the internal network.
o A DOTS gateway is enabled in each CPE (rtr1, rtr2).
Boucadair & Reddy Expires April 10, 2019 [Page 10]
Internet-Draft DOTS Multihoming October 2018
o Each of these DOTS gateways communicate with the DOTS server of
the provisioning domain.
When PI addresses/prefixes are used, DOTS clients can contact any of
the DOTS gateways to send a DOTS message. DOTS gateway will then
relay the request to the DOTS server. Note that the use of anycast
addresses is NOT RECOMMENDED to establish DOTS signaling sessions
between DOTS client and DOTS gateways.
When PA addresses/prefixes are used, but no filter rules are provided
to DOTS clients, these later MUST contact all DOTS gateways
simultaneously to send a DOTS message. Upon receipt of a request by
a DOTS gateway, it MUST check whether the request is to be forwarded
upstream or be rejected.
When PA addresses/prefixes are used, but specific filter rules are
provided to DOTS clients using some means that are out of scope,
these later MUST select the appropriate DOTS gateway to be contacted.
The use of anycast is NOT RECOMMENDED to reach DOTS gateways.
+---+
+------------| C1|----+
| +---+ |
+--+ +-+-+ +---+ +-+-+ +--+
|S2|------|G2 |------| C3|------|G1 |------|S1|
+--+ +-+-+ +---+ +-+-+ +--+
| +---+ |
+------------| C2|----+
+---+
Figure 9: Multiple DOTS Clients, Multiple DOTS Gateways, Multiple
DOTS Servers
5.4. Multi-homed Enterprise: Single ISP
The key difference of the scenario described in Section 4.4 compared
to the other scenarios is that multi-homing is provided by the same
ISP. Concretely, that ISP can decided to provision the enterprise
network with:
1. The same DOTS server for all network attachments.
2. Distinct DOTS servers for each network attachment. These DOTS
servers needs to coordinate when a mitigation action is received
from the enterprise network.
Boucadair & Reddy Expires April 10, 2019 [Page 11]
Internet-Draft DOTS Multihoming October 2018
In both cases, DOTS agents enabled within the enterprise network may
decide to select one or all network attachments to place DOTS
mitigation requests.
6. Security Considerations
DOTS-related security considerations are discussed in Section 4 of
[I-D.ietf-dots-architecture].
TBD: In Home networks, if EST is used then how will the DOTS gateway
(EST client) be provisioned with credentials for initial enrolment
(see Section 2.2 in RFC 7030).
7. IANA Considerations
This document does not require any action from IANA.
8. Acknowledgements
Thanks to Roland Dobbins and Nik Teague for sharing their comments on
the mailing list.
Thanks to Kirill Kasavchenko for the comments.
9. References
9.1. Normative References
[I-D.ietf-dots-architecture]
Mortensen, A., Andreasen, F., K, R.,
christopher_gray3@cable.comcast.com, c., Compton, R., and
N. Teague, "Distributed-Denial-of-Service Open Threat
Signaling (DOTS) Architecture", draft-ietf-dots-
architecture-07 (work in progress), September 2018.
[RFC2119] Bradner, S., "Key words for use in RFCs to Indicate
Requirement Levels", BCP 14, RFC 2119,
DOI 10.17487/RFC2119, March 1997,
<https://www.rfc-editor.org/info/rfc2119>.
[RFC6724] Thaler, D., Ed., Draves, R., Matsumoto, A., and T. Chown,
"Default Address Selection for Internet Protocol Version 6
(IPv6)", RFC 6724, DOI 10.17487/RFC6724, September 2012,
<https://www.rfc-editor.org/info/rfc6724>.
[RFC8174] Leiba, B., "Ambiguity of Uppercase vs Lowercase in RFC
2119 Key Words", BCP 14, RFC 8174, DOI 10.17487/RFC8174,
May 2017, <https://www.rfc-editor.org/info/rfc8174>.
Boucadair & Reddy Expires April 10, 2019 [Page 12]
Internet-Draft DOTS Multihoming October 2018
9.2. Informative References
[I-D.boucadair-dots-server-discovery]
Boucadair, M., K, R., and P. Patil, "Distributed-Denial-
of-Service Open Threat Signaling (DOTS) Server Discovery",
draft-boucadair-dots-server-discovery-04 (work in
progress), April 2018.
[I-D.ietf-dots-data-channel]
Boucadair, M., K, R., Nishizuka, K., Xia, L., Patil, P.,
Mortensen, A., and N. Teague, "Distributed Denial-of-
Service Open Threat Signaling (DOTS) Data Channel
Specification", draft-ietf-dots-data-channel-22 (work in
progress), September 2018.
[I-D.ietf-dots-signal-channel]
K, R., Boucadair, M., Patil, P., Mortensen, A., and N.
Teague, "Distributed Denial-of-Service Open Threat
Signaling (DOTS) Signal Channel Specification", draft-
ietf-dots-signal-channel-25 (work in progress), September
2018.
[I-D.ietf-dots-use-cases]
Dobbins, R., Migault, D., Fouant, S., Moskowitz, R.,
Teague, N., Xia, L., and K. Nishizuka, "Use cases for DDoS
Open Threat Signaling", draft-ietf-dots-use-cases-16 (work
in progress), July 2018.
[RFC3582] Abley, J., Black, B., and V. Gill, "Goals for IPv6 Site-
Multihoming Architectures", RFC 3582,
DOI 10.17487/RFC3582, August 2003,
<https://www.rfc-editor.org/info/rfc3582>.
[RFC4116] Abley, J., Lindqvist, K., Davies, E., Black, B., and V.
Gill, "IPv4 Multihoming Practices and Limitations",
RFC 4116, DOI 10.17487/RFC4116, July 2005,
<https://www.rfc-editor.org/info/rfc4116>.
[RFC4732] Handley, M., Ed., Rescorla, E., Ed., and IAB, "Internet
Denial-of-Service Considerations", RFC 4732,
DOI 10.17487/RFC4732, December 2006,
<https://www.rfc-editor.org/info/rfc4732>.
[RFC7556] Anipko, D., Ed., "Multiple Provisioning Domain
Architecture", RFC 7556, DOI 10.17487/RFC7556, June 2015,
<https://www.rfc-editor.org/info/rfc7556>.
Boucadair & Reddy Expires April 10, 2019 [Page 13]
Internet-Draft DOTS Multihoming October 2018
[RFC8043] Sarikaya, B. and M. Boucadair, "Source-Address-Dependent
Routing and Source Address Selection for IPv6 Hosts:
Overview of the Problem Space", RFC 8043,
DOI 10.17487/RFC8043, January 2017,
<https://www.rfc-editor.org/info/rfc8043>.
Authors' Addresses
Mohamed Boucadair
Orange
Rennes 35000
France
Email: mohamed.boucadair@orange.com
Tirumaleswar Reddy
McAfee, Inc.
Embassy Golf Link Business Park
Bangalore, Karnataka 560071
India
Email: TirumaleswarReddy_Konda@McAfee.com
Boucadair & Reddy Expires April 10, 2019 [Page 14]
