IPv6 in the Home

A transition technology realized

EarthLink Research and Development


Introducing IPv6 to the Home Network

IPv6 solves a number of problems which obtain on the Internet today. These include address space exhaustion, stateless autoconfiguration, and low cost restoration of end-to-end addressability in the face of ubiquitous network address translation (NAT).

EarthLink Research and Development offers a glimpse of the future of home networking by reworking the open source firmware of the popular Linksys model WRT54G™ home gateway. The firmware rework enables the WRT54G to a) acquire a publicly routeable /64 IPv6 prefix, b) provide IPv6 addresses from that prefix to hosts on the home network, and c) route IPv6 home network traffic to the greater IPv6 Internet. (This firmware is not a supported EarthLink or Linksys product. Please see the Disclaimer below).

The firmware modification does not affect the ability of the WRT54G to support IPv4 traffic as it was designed to do. IPv4 and IPv6 traffic coexist on the home network side by side without interfering with each other. This dual IPv4/IPv6 support makes the WRT54G with the added IPv6 functionality a perfect model IPv6 transition device.

With publicly routeable IPv6 support, the firmware demonstrates a return to the characteristic that makes Internet Protocol so centrally important to modern communications: end to end addressability. With the restoration of IPv6-based end-to-end, no longer must applications deal with the cost, unpredictability, and wide variation in implementation details of network address translation. IPv6 to the home lifts the "NAT tax".

Features

Motivation

The invention of network address translation (NAT) was an unqualified boon to home networking when it was introduced in consumer home routers several years ago. NAT gave us the ability to create home networks without the costly overhead of publicly routeable IPv4 address delegation bookkeeping.

While NAT allowed easy creation of home networks, it had a downside: home networks were not directly addressable from the outside Internet because of NAT's use of non routeable addresses. As a result, the end-to-end principle was broken. The consequences of breaking end-to-end by using non routeable addresses include the need for media handling for services such as VoIP and other widely enjoyed Internet amusements, such as some online games. The consequences of NAT are especially serious in the realm of peer-to-peer computing, where core services rely upon peers addressing other peers directly, without the need for mediating servers in the middle. We wanted to restore end-to-end to the Internet. Hence the IPv6-enabled firmware work.

Observations on home network security

While NAT can make it difficult for legitimate applications to function properly, it has one major upside: it almost completely protects the home network from intrusion attempts. Since no machines on the home network have a publicly routable IP addresses, it is not possible for an intruder to attempt to communicate directly with those machines unless the NAT box is specifically configured to enable such traffic.

The IPv6-enabled firmware makes all machines on the home network publicly accessible. Any machine on the internet with a globally routeable IPv6 address may try and access any machine on the home network directly. To try and mitigate the risk to the home network, our firmware ships with a very restrictive firewall setting by default. Users may modify the firewall settings to meet their needs, or may decide to disable it. By default, however, the firmware only permits incoming TCP connections on port 22 (SSH). Inbound traffic to high UDP ports (those above 1024) is also permitted. All other inbound traffic is denied.

Disclaimer

The EarthLink R&D modified firmware for the Linksys WRT54G is a prototype, meant to be used casually for instructional, evaluation, and amusement purposes. It is alpha-quality code at best, and not suitable for any purpose. The version you download here may contain bugs introduced unintentionally by us, although we are not aware of any. The software is provided as-is, with no warranty expressed or implied, as described in the license(s) accompanying the source to the software.

Finally, EarthLink R&D will from time to time release code, such as our Conference Manager and SIPshare, on a proof-of-concept basis. We like to gauge what the community is interested in, to see what ideas may find purchase in the greater Internet user base.

As a result of all this, the EarthLink R&D produced firmware modification for the Linksys WRT54G is NOT a supported EarthLink product and is NOT a supported Linksys product. It is more than anything else a demonstration of what home networking can be when end-to-end addressing is restored. So if you call EarthLink Tech Support or Linksys Tech Support with questions on this firmware, they will have no idea what you are talking about and will be unable to help you.

That said, a user forum has been created for user-to-user support, in which EarthLink R&D will participate as resources allow. Questions and comments may also be mailed to ipv6 at research.earthlink.net.

Service levels and network abuse

While there is no charge for using the EarthLink R&D IPv6 routing services, this is an experimental pilot project and may be discontinued at any time without notice. There are no service level guarantees expressed or implied. IPv6 traffic must be kept to within what EarthLink R&D considers reasonable levels. Bandwidth and network abusers will have their accounts cancelled at our discretion.

Trademarks

Microsoft Windows is a trademark of Microsoft Corporation. Mac OS X is a trademark of Apple Corporation. WRT54G is a trademark of Linksys and Cisco Systems. Linux is a trademark of Linus Torvalds. FreeBSD is a trademark of The FreeBSD Foundation.

Download the firmware
Installation and uninstallation
Create/manage an account
Quick test of IPv6 connectivity
User forum
FAQ
A writeup of how this entire system was created

Last modified: Wed Jul 06 18:29:15 PDT 2005
Feedback: ipv6 at research.earthlink.net
Copyright 2005, EarthLink, Inc.
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