draft-ietf-dhc-dynamic-shared-v4allocation-08.txt   draft-ietf-dhc-dynamic-shared-v4allocation-09.txt 
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Deutsche Telekom AG Deutsche Telekom AG
Y. Lee Y. Lee
Comcast Comcast
Q. Sun Q. Sun
China Telecom China Telecom
M. Boucadair M. Boucadair
France Telecom France Telecom
May 28, 2015 May 28, 2015
Dynamic Allocation of Shared IPv4 Addresses Dynamic Allocation of Shared IPv4 Addresses
draft-ietf-dhc-dynamic-shared-v4allocation-08 draft-ietf-dhc-dynamic-shared-v4allocation-09
Abstract Abstract
This memo describes the dynamic allocation of shared IPv4 addresses This memo describes the dynamic allocation of shared IPv4 addresses
to clients using DHCPv4. Address sharing allows a single IPv4 to clients using DHCPv4. Address sharing allows a single IPv4
address to be allocated to multiple active clients simultaneously, address to be allocated to multiple active clients simultaneously,
each client being differentiated by a unique set of transport layer each client being differentiated by a unique set of transport layer
source port numbers. The necessary changes to existing DHCPv4 client source port numbers. The necessary changes to existing DHCPv4 client
and server behavior are described and a new DHCPv4 option for and server behavior are described and a new DHCPv4 option for
provisioning clients with shared IPv4 addresses is included. provisioning clients with shared IPv4 addresses is included.
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6. Client-Server Interaction . . . . . . . . . . . . . . . . . . 4 6. Client-Server Interaction . . . . . . . . . . . . . . . . . . 4
7. Client Behavior . . . . . . . . . . . . . . . . . . . . . . . 5 7. Client Behavior . . . . . . . . . . . . . . . . . . . . . . . 5
7.1. Restrictions to Client Usage of a Shared IPv4 Address . . 6 7.1. Restrictions to Client Usage of a Shared IPv4 Address . . 6
8. Server Behavior . . . . . . . . . . . . . . . . . . . . . . . 7 8. Server Behavior . . . . . . . . . . . . . . . . . . . . . . . 7
8.1. Leasing Shared and Non-Shared IPv4 Addresses from a 8.1. Leasing Shared and Non-Shared IPv4 Addresses from a
Single DHCP 4o6 Server . . . . . . . . . . . . . . . . . 8 Single DHCP 4o6 Server . . . . . . . . . . . . . . . . . 8
9. DHCPv4 Port Parameters Option . . . . . . . . . . . . . . . . 8 9. DHCPv4 Port Parameters Option . . . . . . . . . . . . . . . . 8
10. Security Considerations . . . . . . . . . . . . . . . . . . . 9 10. Security Considerations . . . . . . . . . . . . . . . . . . . 9
10.1. Port Randomization . . . . . . . . . . . . . . . . . . . 10 10.1. Port Randomization . . . . . . . . . . . . . . . . . . . 10
11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10 11. IANA Considerations . . . . . . . . . . . . . . . . . . . . . 10
12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 10 12. Acknowledgements . . . . . . . . . . . . . . . . . . . . . . 11
13. References . . . . . . . . . . . . . . . . . . . . . . . . . 11 13. References . . . . . . . . . . . . . . . . . . . . . . . . . 11
13.1. Normative References . . . . . . . . . . . . . . . . . . 11 13.1. Normative References . . . . . . . . . . . . . . . . . . 11
13.2. Informative References . . . . . . . . . . . . . . . . . 11 13.2. Informative References . . . . . . . . . . . . . . . . . 12
Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 12 Authors' Addresses . . . . . . . . . . . . . . . . . . . . . . . 13
1. Introduction 1. Introduction
The shortage of available public IPv4 addresses means that it is not The shortage of available public IPv4 addresses means that it is not
always possible for operators to allocate a full IPv4 address to always possible for operators to allocate a full IPv4 address to
every connected device. This problem is particularly acute whilst an every connected device. This problem is particularly acute whilst an
operator is migrating from their existing, native IPv4 network to a operator is migrating from their existing, native IPv4 network to a
native IPv6 network with IPv4 provided as an overlay service. During native IPv6 network with IPv4 provided as an overlay service. During
this phase, public IPv4 addresses are needed to provide for both this phase, public IPv4 addresses are needed to provide for both
existing and transition networks. existing and transition networks.
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unicast DHCP 4o6 message flows (enabled by supplying DHCP 4o6 server unicast DHCP 4o6 message flows (enabled by supplying DHCP 4o6 server
unicast addresses within the OPTION_DHCP4_O_DHCP6_SERVER option). unicast addresses within the OPTION_DHCP4_O_DHCP6_SERVER option).
A malicious user could attempt a DoS attack by requesting a large A malicious user could attempt a DoS attack by requesting a large
number ofIPv4 address (or fractional address) and port sets number ofIPv4 address (or fractional address) and port sets
allocations, exhausting the available addresses and port sets for allocations, exhausting the available addresses and port sets for
other clients. This can be mitigated through DHCP 4o6 address other clients. This can be mitigated through DHCP 4o6 address
allocation policy, limiting the number of simultaneously active IPv4 allocation policy, limiting the number of simultaneously active IPv4
leases for clients whose request originate from each customer site. leases for clients whose request originate from each customer site.
The purpose of the client identifier option is to ensure that the
same client retains the same parameters over time. This interferes
with the client's privacy, as it allows the server to track the
client. Clients can manage their privacy exposure by controlling the
value of the client identifier, trading off stability of parameter
allocation for privacy. We expect that guidance on this trade-off
will be discussed in a future version of
[I-D.ietf-dhc-anonymity-profile].
Additional security considerations are discussed in Section 11 of Additional security considerations are discussed in Section 11 of
[I-D.ietf-softwire-map] and Section 9 of [I-D.ietf-softwire-map] and Section 9 of
[I-D.ietf-softwire-lw4over6]. [I-D.ietf-softwire-lw4over6].
10.1. Port Randomization 10.1. Port Randomization
Preserving port randomization [RFC6056] may be more difficult because Preserving port randomization [RFC6056] may be more difficult because
the host can only randomize the ports inside a fixed port range (see the host can only randomize the ports inside a fixed port range (see
Section 13.4 of [RFC6269]). Section 13.4 of [RFC6269]).
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OPTION_V4_PORTPARAMS TBA 4 This option is used to configure a OPTION_V4_PORTPARAMS TBA 4 This option is used to configure a
set of ports bound to a shared IPv4 set of ports bound to a shared IPv4
address. address.
12. Acknowledgements 12. Acknowledgements
This document is merged from [I-D.sun-dhc-port-set-option] and This document is merged from [I-D.sun-dhc-port-set-option] and
[I-D.farrer-dhc-shared-address-lease]. [I-D.farrer-dhc-shared-address-lease].
The authors would like to thank Peng Wu, Gabor Bajko, Teemu The authors would like to thank Peng Wu, Gabor Bajko, Teemu
Savolainen, Ted Lemon, Tina Tsou, Pierre Levis, Cong Liu, and Marcin Savolainen, Ted Lemon, Tina Tsou, Pierre Levis, Cong Liu, Marcin
Siodelski for their contributions. Siodelski, and Christian Huitema for their contributions.
Many thanks to Brian Haberman for the review. Many thanks to Brian Haberman for the review.
13. References 13. References
13.1. Normative References 13.1. Normative References
[I-D.ietf-softwire-lw4over6] [I-D.ietf-softwire-lw4over6]
Cui, Y., Qiong, Q., Boucadair, M., Tsou, T., Lee, Y., and Cui, Y., Qiong, Q., Boucadair, M., Tsou, T., Lee, Y., and
I. Farrer, "Lightweight 4over6: An Extension to the DS- I. Farrer, "Lightweight 4over6: An Extension to the DS-
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Farrer, "DHCPv4-over-DHCPv6 (DHCP 4o6) Transport", RFC Farrer, "DHCPv4-over-DHCPv6 (DHCP 4o6) Transport", RFC
7341, August 2014. 7341, August 2014.
13.2. Informative References 13.2. Informative References
[I-D.farrer-dhc-shared-address-lease] [I-D.farrer-dhc-shared-address-lease]
Farrer, I., "Dynamic Allocation of Shared IPv4 Addresses Farrer, I., "Dynamic Allocation of Shared IPv4 Addresses
using DHCPv4 over DHCPv6", draft-farrer-dhc-shared- using DHCPv4 over DHCPv6", draft-farrer-dhc-shared-
address-lease-00 (work in progress), June 2013. address-lease-00 (work in progress), June 2013.
[I-D.ietf-dhc-anonymity-profile]
Huitema, C., Mrugalski, T., and S. Krishnan, "Anonymity
profile for DHCP clients", draft-ietf-dhc-anonymity-
profile-00 (work in progress), May 2015.
[I-D.ietf-softwire-map-dhcp] [I-D.ietf-softwire-map-dhcp]
Mrugalski, T., Troan, O., Farrer, I., Perreault, S., Dec, Mrugalski, T., Troan, O., Farrer, I., Perreault, S., Dec,
W., Bao, C., Yeh, L., and X. Deng, "DHCPv6 Options for W., Bao, C., Yeh, L., and X. Deng, "DHCPv6 Options for
configuration of Softwire Address and Port Mapped configuration of Softwire Address and Port Mapped
Clients", draft-ietf-softwire-map-dhcp-12 (work in Clients", draft-ietf-softwire-map-dhcp-12 (work in
progress), March 2015. progress), March 2015.
[I-D.sun-dhc-port-set-option] [I-D.sun-dhc-port-set-option]
Qiong, Q., Lee, Y., Sun, Q., Bajko, G., and M. Boucadair, Qiong, Q., Lee, Y., Sun, Q., Bajko, G., and M. Boucadair,
"Dynamic Host Configuration Protocol (DHCP) Option for "Dynamic Host Configuration Protocol (DHCP) Option for
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