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At-Large Community IPv6 Frequently Asked Questions

At-Large Community IPv6 Frequently Asked Questions

This FAQ was produced by members of the At-Large Community for the At-Large Summit in March 2009.

A. Fundamental questions

A1. What is IPv6?
A2. Why is there a need for IPv6?
A3. What is the format and syntax of an IPv6 address?
A4. Can IPv4 and IPv6 co-exist?

B. User perspective - Access

B1. How do I turn on IPv6 in Windows XP?
B2. How do I turn on IPv6 in Vista?
B3. How do I turn on IPv6 on my Mac?
B4. How do I turn on IPv6 on other operating systems?
B5. How do I access the Internet using IPv6?
a. Native IPv6
b. Using IPv6 over IPv4 by Tunneling (Teredo, 6to4, 6in4, etc.)
- Windows: Teredo Tunneling
- Mac OS X: Teredo Tunneling
- MAC OS X: 6to4 Tunneling
- 6to4 and 6in4 for other Operating Systems
c. Special Case: mobile devices (PDAs, etc.)

C. Burning questions

C1. Is IPv6 likely to introduce new security vulnerabilities?
C2. Is IPv6 faster or slower than IPv4?
C3. Can I do things with IPv6 that I can't do with IPv4?
C4. Is IPv4 going to be shut down?
C5. What hardware devices (ADSL modems etc.) are IPv6 compatible?
C6. What ISPs offer IPv6 service?
C7. I'm curious - what happened to IPv5?
C8. Where can I find further information about IPv6?

 

A. Fundamental questions

A1. What is IPv6?

IPv6 is a new version of the Internet Protocol (IP for short). In the future, it will replace the current IPv4 protocol that is currently used on the Internet.

A2. Why is there a need for IPv6?

Mostly because IPv4 addresses are becoming a scarce resource.

Every device connected to the Internet needs its own IP address. In IPv4, there is a theoretical maximum of 4,294,967,296 IP addresses (that's about 4.2 Billion), which might seem like a high number, but when you count the fact that we are 6.5 Billion people on Earth and that every piece of telecommunications equipment related to Internet connectivity needs its own IP addresses, it is not enough, especially since some of this space is used for routing and sub-netting purposes.

Again, in theory, IPv6 allows 3.4×10 38 addresses - that's 340,282,366,920,938,463,463,374,607,431,770,000,000 addresses, which is a very large number indeed!

It means that every human on Earth could in theory use 5x10 28, that's roughly 50,000,000,000,000,000,000,000,000,000 IP addresses - which is enough for your home computer, your laptop, your mobile phone, your PDA, your robot, and virtually anything electronic around you.

If we want to connect the next billion Internet users, we will need IPv6.

A3. What is the format and syntax of an IPv6 address?

IPv4 relied on 32 bit addresses, expressed in 4 octets, for example 192.168.10.1

IPv6 uses 128 bit addresses expressed in hexadecimal numbers (with letters not case-sensitive), represented in 8 groups and separated by colons, for example:

2001:0db8:85a3:0000:0000:8a2e:0370:7334

It's rather long, so this address can be shortened, by removing the leading zeros in each group:

2001:db8:85a3:0:0:8a2e:370:7334

One instance of one or any number of consecutive groups of 0 value may be replaced with a single set of two colons (::):

2001:db8:85a3::8a2e:370:7334

Note that this substitution with double-colon may be performed only once in an address, because multiple occurrences would lead to ambiguity.

At first glance, shortening addresses might be confusing, but once you get the hang of it, it's quite simple.

The localhost address, 0000:0000:0000:0000:0000:0000:0000:0001 can be written simply as ::1

The first group, shown in our example as 2001, is called a prefix and is used to qualify address type. Those are too numerous to list here, but a list is maintained by IANA and can be found at:

http://www.iana.org/assignments/iana-ipv6-special-registry

http://www.iana.org/assignments/ipv6-tla-assignments

http://www.iana.org/assignments/ipv6-unicast-address-assignments

IPv4 addresses can be written in IPv6 notation by writing the address in hexadecimal format in the last four groups of an IPv6 address, preceded by a "ffff".

For example, 192.168.10.1 can be written as ::ffff:c0a8:a01 which really is: 0000:0000:0000:0000:0000:ffff:c0a8:0a01

A search for "IPv4 to IPv6 address converter" on your favorite search engine will reveal several web sites offering free conversion of addresses to hexadecimal format.

A4. Can IPv4 and IPv6 co-exist?

Not only can they coexist, but they actually need to!

The transition from IPv4 to IPv6 will take several years, during which time both protocols need to be used. Whilst there are still a few issues in isolated cases of IPv4/IPv6 co-existence, software and hardware vendors are working hard to resolve them and there should be no serious reason for both protocols not to co-exist for years to come.

B. User perspective - Access

Whilst many recent operating systems advertise native Ipv6 support, there are several tricks required to actually make it work in a useful way. One major obstacle is the home router/modem. At the time of writing, most do not support IPv6. Some require hacking tricks to update their firmware.

Right now, the easiest way for a user using a PC running windows is to use a "Teredo" tunnel, because it only requires changing parameters on the local computers. For a MAC, various solutions exist. Both cases are described in Question B5.b.

B1. How do I turn on IPv6 in Windows XP?

IPv6 has been added to Windows XP SP2 as standard, but a procedure is required to enable it.

Please refer to this document to set-up IPv6 on Windows XP:

http://yorickdowne.wordpress.com/2008/01/26/ipv6-at-home-part-1-overview-teredo/

Also Microsoft’s extensive IPv6 FAQ:

http://www.microsoft.com/technet/network/ipv6/ipv6faq.mspx

B2. How do I turn on IPv6 in Vista?

IPv6 in Windows Vista is only usable on a home computer if some default values are changed, as shown here:

http://yorickdowne.wordpress.com/2008/01/26/ipv6-at-home-part-1-overview-teredo/

Also Microsoft’s extensive IPv6 FAQ:

http://www.microsoft.com/technet/network/ipv6/ipv6faq.mspx

B3. How do I turn on IPv6 on my Mac?

Although IPv6 on the Mac is enabled by default, there are only few applications that can use it out of the box with the defaults. For example, "Back to My Mac" is an Apple service that uses IPv6.

With time, more and more Mac applications will start using IPv6.

B4. How do I turn on IPv6 on other operating systems?

Most recent operating systems (Most distributions of Linux, *BSD, OpenSolaris and others) have IPv6 enabled by default. Again, how useful the defaults are, is very dependent on the local context.

In most cases, a hardware IPv6 address with prefix fe80 is set-up by default, and derived from the Ethernet's MAC address. These addresses are non-routable, so specific IPv6 addresses will have to be set-up for each Ethernet port.

Each software distribution will include details on how to configure IPv6. One item to remember is that the Firewall default for IPv4 is completely separate from the Firewall default for IPv6.

Firewall defaults vary between manufacturers with some allowing all traffic and others blocking it. In order to avoid security breaches, but also a lot of time wasted trying to debug connectivity problems, it is very important that you understand the capabilities and defaults of your Firewall in advance of enabling IPv6.

B5. How do I access the Internet using IPv6?

a. Native IPv6

You need to set-up your computer to use IPv6 (see above). You then need to connect to the Internet directly using IPv6. This is only possible if your local gateway supports IPv6 and your connection to the Internet is IPv6 enabled.

Not having a direct IPv6 connection to the Internet doesn't preclude you to using IPv6 since you can achieve this using IPv6 over IPv4 Tunneling. This is described next.

b. Using IPv6 over IPv4 by Tunneling (Teredo, 6to4, 6in4, etc.)

Tunneling is a technique whereas traffic is encapsulated in a different type of protocol, for example in order to carry a payload across an incompatible network or to provide a secure path through an unsecure network. Tunneling can therefore be used set-up an IPv6 connection through an IPv4 tunnel, thus allowing access to IPv6 when your local Internet Service Provider only offers IPv4 service.

Tunneling requires the use of a remote end point at which the tunnel will end, and IPv6 traffic will then be carried in a native IPv6 network. This might be automated or might require human intervention to set-up.

- Windows: Teredo Tunneling

Teredo is a tunneling protocol designed to grant IPv6 connectivity to nodes that are located behind IPv6-unaware network devices. It defines a way of encapsulating IPv6 packets within IPv4, thus enabling users to have IPv6 connectivity whilst their internet service provider only supplies IPv4 connectivity.

This page contains information on how to set-up Teredo:

http://yorickdowne.wordpress.com/2008/01/26/ipv6-at-home-part-1-overview-teredo/

- Mac OS X: Teredo Tunneling

One way would be to use Teredo Tunneling with the Miredo client. For instructions on how to do this, see:

http://www.deepdarc.com/miredo-osx/

- Mac OS X: 6to4 Tunneling

Mac users can also make use of an Apple AirPort Extreme base station which has excellent support for 6to4 Tunneling functionality and can therefore allow IPv6 connectivity even if your ISP only offers IPv4.

- 6to4 and 6in4 for other Operating Systems

Most other Operating Systems can run Tunneling protocols named 6in4 and 6to4. In some cases, an additional piece of software is required, but in others, everything that's needed to set-up a tunnel is included in the software distribution.

6to4 and 6in4 are used by Linux/Unix clients as well as programmable routers. Use your favorite search engine to find what is required.

The following pages provide a good introduction of 6to4 and 6in4:

http://en.wikipedia.org/wiki/6to4

http://en.wikipedia.org/wiki/6in4

c. Special Case: mobile devices (PDAs, etc.)

Most of these are not yet IPv6 enabled. With time, more and more mobile devices will be IPv6 enabled.

C. Burning questions

C1. Is IPv6 likely to introduce new security vulnerabilities?

Traditionally, Network Address Translation (NAT) has been used to forward incoming traffic to specific IPv4 addresses and this has, to some extent, reduced the number of devices in a local area network being accessible directly from outside.

Using IPv6 allocates addresses which are theoretically all routable through the Internet. This might constitute a security threat. The emphasis of setting up NAT correctly in the router is therefore now shifting to setting up the Firewall correctly.

It is also worth knowing that IPv6 tunneling allows a path through IPv4 firewalls. Attackers might be able to penetrate your network if you don't set-up the IPv6 firewall.

C2. Is IPv6 faster or slower than IPv4?

Theoretically, IPv6 is neither faster nor slower than IPv4. However, the use of gateways like Teredo and 6to4 tunnels in various flavors tends to add an overhead.

Furthermore, peering agreements among ISPs and transit providers are not as optimal for IPv6 as they are now for IPv4. This may result in perceived slower response. However, this will fade away when IPv6 is widely deployed.

C3. Can I do things with IPv6 that I can't do with IPv4?

Yes, you can see the dancing turtle at www.kame.net. There is a list of cool Ipv6 only stuff at http://www.sixxs.net/misc/coolstuff/

More seriously, IPv6 opens a wealth of possibilities to application designers:

Because with IPv6, each device behind a home router can have a dedicated IP address, there is no need for them to revert to complicated tricks like Network Address Translation. You could then access each one of your IPv6 devices remotely. The standard allocation for a home user is still currently in discussion but proposals have been made for anything between a "/64", to "/56" and "/48" networks. That is, you will be able to have between 18,446,744,073,709,551,616 to 1,208,925,819,614,629,174,706,176 (in US nomenclature it is 18.4 quintillion to 1.2 Septillion) directly accessible devices on your home network!

That beats any current allocation possible with IPv4.

Consumer Electronic manufacturers are preparing themselves for this revolution by developing standards where your TV, Mp3, storage drive, computer, and virtually any other electronic device will be able to correspond with the others. This is particularly exciting! For more information, try:

http://www.dlna.org/industry/why_dlna/key_components/network/

The first products supporting this standard have appeared on the market since the end of 2008.

C4. Is IPv4 going to be shut down?

In the short term and medium term, the answer is plainly no.

In the long term, it is impossible to say. Market forces are likely to prevail.

However, there is likely to be a difference between countries. What happens to IPv4 access will probably vary based on existing market conditions and availability of local content: If there is plenty of local content already on IPv4, the likelihood of reducing IPv4 access is less likely than if little local content is available, primarily because new

local content is likely to make use of both IPv4 and IPv6 access and eventually, IPv6 only access.

C5. What hardware devices (ADSL modems etc.) are IPv6 compatible?

The vast majority of DSL/cable modems and routers are not yet IPv6 enabled.

Some can be made Ipv6 aware with a firmware update like OpenWRT, DD-WRT for the Linksys 54G router.

Some ISPs like Comcast in the US and Free in France provide their proprietary modems, which are IPv6 enabled.

Major router manufacturers like CISCO have already made software updates available for most of their router range to be IPv6 compatible.

The Apple AirPort Extreme Docking Station also has excellent support for 6to4 tunneling.

C6. What ISPs offer IPv6 service?

The list is growing daily, so check with your favourite search engine.

For a partial list, please see:

http://www.sixxs.net/faq/connectivity/?faq=native

C7. I'm curious - what happened to IPv5?

This was an experimental protocol which was developed in the 1980s and which was never widely deployed. When considering successors to IPv4, several technologies were proposed, each with a version number, and number 6 was selected.

C8. Where can I find further information about IPv6?

Try:

http://www.isoc.org/educpillar/resources/ipv6_faq.shtml

http://en.wikipedia.org/wiki/IPv6

http://de.wikipedia.org/wiki/Ipv6 (In German)

http://es.wikipedia.org/wiki/Ipv6 (In Spanish)

http://fr.wikipedia.org/wiki/Ipv6 (In French)

http://pt.wikipedia.org/wiki/Ipv6 (In Portuguese)

http://www.getipv6.info/index.php/Main_Page (ARIN's IPv6 page)

http://www.ipv6tf.org

...and many more!