Network Working Group M. Andrews
Internet-Draft ISC
Intended status: Standards Track May 9, 2011
Expires: November 10, 2011
6to4 DHCP Router Option
draft-andrews-v6ops-6to4-router-option-00
Abstract
Provides a DHCP 6to4 Relay Router option.
Status of this Memo
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Table of Contents
1. Introduction . . . . . . . . . . . . . . . . . . . . . . . . . 3
2. 6to4 Relay Router Option . . . . . . . . . . . . . . . . . . . 3
3. IANA Considerations . . . . . . . . . . . . . . . . . . . . . . 3
4. Security Considerations . . . . . . . . . . . . . . . . . . . . 3
5. Normative References . . . . . . . . . . . . . . . . . . . . . 4
Author's Address . . . . . . . . . . . . . . . . . . . . . . . . . 4
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1. Introduction
Using 6to4 [RFC 3056] currently requires manual configuration of the
relay router or the use of a anycast relay router [RFC 3068]. The
latter has a number of well known issues (add reference).
This document attempts to address some of those issues by providing a
method for clients to discover the address of a 6to4 relay router.
It is expected that the 6to4 relay router will be managed and that it
will be topologically close to the client thereby reducing some of
the issues with using public anycast relay routers.
Additionally not all IPv4 address allocated to clients are suitable
for use with 6to4. Whether they be [RFC 1918] address, or other
addresses behind a NAT, or are behind a firewall which blocks 6to4
encapsulted traffic. This document provides a method for the DHCP
server operator to signal that the address being returned is not
suitable for use with 6to4.
2. 6to4 Relay Router Option
The 6to4 DHCP relay option has code TBD and consists of a single IPv4
address specifing the IPv4 address of the 6to4 relay router. Setting
the relay router address to 0.0.0.0 indicates that 6to4 will not work
for returned lease address.
0 1 2 3
0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1 2 3 4 5 6 7 8 9 0 1
+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+-+
| TBD | 4 | relay router ~
+---------------+---------------+---------------+---------------+
~ address |
+-------------------------------+
3. IANA Considerations
IANA is requested to allocate a DHCP option code point.
4. Security Considerations
A rogue DHCP server advertising this option can cause 6to4 traffic to
be redirected anywhere in the world.
Setting the returned address to 0.0.0.0 can be used to deny 6to4
service when it would otherwise work.
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5. Normative References
[RFC 1918]
Rekhter, Y., Moskowitz, B., Karrenberg, D., de Groot, G.,
and E. Lear, "Address Allocation for Private Internets",
BCP 5, RFC 1918, February 1996.
[RFC 3056]
Carpenter, B. and K. Moore, "Connection of IPv6 Domains
via IPv4 Clouds", RFC 3056, February 2001.
[RFC 3068]
Huitema, C., "An Anycast Prefix for 6to4 Relay Routers",
RFC 3068, June 2001.
Author's Address
Mark P. Andrews
Internet Systems Consortium
950 Charter Street
Redwood City, CA 94063
US
Email: marka@isc.org
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