Windows 8 IPv6

Windows 8 IPv6

Migration to IPv6 is very slow, but Windows 8 is ready and waiting for a move away from IPv4.

• Windows 8 IPv6 in 2013
• Why Will We Need IPv6?
• Five Useful IPv6 Concepts
• IPv6 Maths – See the Big Picture
• Making Sense of the Hex Numbers

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Windows 8 IPv6 in 2013

Probably the best thing you can do about IPv6 in 2013 is nothing.  Just leave each IPv6 setting as the default.  Windows 8 has been cleverly programmed to use IPv6 if possible, but revert to IPv6 if that's what it takes to make the connection.

If You Need to Configure IPv6 in Windows 8
To get started launch the Control Panel:

• Network and Internet\Network and Sharing Center.
• Click on the 'Change adapter settings' link.
• Seek the 'Properties' sheet for your NIC.
• Experment by disabling Internet Protocol Version 4.

Note: Both IPv6 and IPv4 are configured as dynamic (not static) by default.

Result From Running Ipconfig /All

Note: Observe v6 settings and corresponding values.

Why Will We Need IPv6?

The driver for the uptake of 128-bit IPv6 will be the shortage of 32-bit IPv4 addresses on the internet.  IPv6 is also cleverer, for example it can overcome the lack of security and prioritization of IPv4 datagrams.

In the mid-term we are beset with compatibility problems because IPv4-only clients cannot communicate with IPv6-only routers.  Thus for most business scenarios migrating to an IPv6-only network is not the answer just yet.

Until IPv4 is switched off, networks will need to cater for both protocol stacks, and develop strategies to work seamlessly with both types of IP node.

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Five Useful IPv6 Concepts

Here are five concepts to lookout for in IPv6 articles, Stateful and Stateless; Link-Local and Site-Local addresses, also Neighbor Discovery (ND)

1. Stateful IP addresses are dished out by a DHCP server.  Usually DHCP in addition to the IPv6 hex number, the clients get the address of the default gateway and probably a DNS server or two.
2. Stateless IPv6 addresses are assigned by the host itself, rather like APIPA in IPv4.  This is what happens if there is no DHCP or manual address assignment.
3. Link-local IPv6 addresses only allow connections with neighbors on that subnet or 'link'.  You can identify Link-local addresses because the begin with FE80, also (FC and FD) naturally, Link-local addresses are not forwarded by routers.
4. Site-local means the IPv6 is routable, but not to the internet, thus hosts with Site-Local IPv6 addresses can use private (not ICANN) IP addresses, AND can connect to any other Site-local address within the organization.  Such site-local addresses all start with FEC0.
5. Neighbor Discovery (ND)  This concepts means that machines determine information about their nearest router.  The idea is also that if an IPv6 stack can obtain information about other nodes, then you won’t get the problem of duplicate IP addresses.

IPv6 Changes in Windows 8

Any operating systems running a dual stack (IPv4 and IPv6) is going to face connectivity problems.  Naturally, if there is connectivity for both IPv4 and IPv6 then Windows 8 (or 7) will favor the IPv6 path.  What irritated Windows 7 users is where the OS cannot detect an IPv6 path and there is a delay while it figures out how long to wait trying the non-existent IPv6 path.

In Windows 8 Microsoft has developed a better algorithm than Windows 7, it checks the state of the IPv6 path at initial configuration if no IPv6 connectivity exists it will be marked as unreachable, and the IPv4 will seek the traditional IPv4 route.

There are also changes on the Windows Server 2012, in particular NAT64/DNS64 is now built-in.  This caters for networks running IPv6 internally, but using IPv4 for the internet.  Incidentally, PowerShell v3 on the Server 2012 provides better cmdlets to manage IPv6 configuration options.

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IPv6 Maths – Don't be a Nerd, See the Big Picture

When you look at IP numbers don't try an memorise the big numbers, instead apply estimation, approximation and keep the big picture in view.  My point is that nerds tell us that IPv4 would generate 4,294,967,296 possible IP addresses, in practice it turned out there were only about 17 million useful addresses.  To paraphrase Oscar Wilde’s ‘A cynic (nerd) is a man who knows the price of everything but the value of nothing’.

With the 128bit IPv6 addresses, the same nerds say there should be 340,300,000,000,000,000,000,000,000,000,000,000,000,000 IP addresses.  Guy guestimates that there may be as few as: 18,000,000,000,000 useful IPv6 addresses.  This shortfall is partly due to reserved and unassigned bits in the 128bit address.  The other reason for this reduced number of usable IP addresses is a design feature whereby 64-bits are taken up with the Interface ID (Mac Number).

Even with my surprisingly low estimate, it still means that everybody on the planet could be given 3,000 IP addresses.  One day I see: one IPv6 for the computer, one for their phone, car, fridge, cooker and every other appliance – then some.

IPv6 Address – Making Sense of the Actual Hex Numbers

IPv6 uses hexadecimal, which is base 16 this is why you now see IP addresses containing not only numbers, but also the letters ABCDEF, for example: 2001:0618:71B3:08C3:1319:8C2D:0271:6017.  As you can see, 128-bit numbers are split into 8 groups of 16bit.

IPv4 addresses are base 10, another difference is that each IPv6 group is separated by a colon rather than a dot.  It is readily apparent that this base 16 scheme helps to increase the available IP addresses.  Surprisingly, the hex letters are not case sensitive.

Obviously, private networks won’t need any where near the full range of IPv6 numbers; as a result many of the address values will be zero.  In this circumstance look for compression of the zeros, instead of FD01:0000:0000:0000:0000:0000:0000:0005, you will see FD01::5.  Note the double colon :: indicating compression of the intervening zeros.  Thus the term ‘compression’ in IPv6 refers to the notation and not to the protocol packets themselves.  Remember that you can only use the double colon once in each IP address.

IPv6 and MAC Address
The biggest reason that there will be fewer IPv6 addresses than the theoretical maximum is that each 64-bit number contains the MAC address of the host.  While incorporating the hardware address reduces the available IPv6 nodes, it makes this protocol more efficient, secure and useful than IPv4.

Note how the DUID*  above contains the Physical Address (MAC Address).

 *DUID = DHCP Unique Identifier.
IAID = Application Unique Identifier

See a review of SolarWinds' IPAM 3 »

ZoneID % InterfaceIndex Number

Observe that the Link-local IPv6 address has a %12 at the end of the string of numbers.

Link-local IPv6 Address . . . . . : fe80::6d96:1610:2097:c45%12(Preferred)

If you run the following PowerShell command it will reveal the InterfaceIndex number:

Compare the results of Ipconfig /all and Get-NetIPConfiguration:

Link-local IPv6 Address . . . . . : fe80::6d96:1610:2097:c45%12(Preferred)

The signifcance of this number is when you use ping.  Assume the destination IPv6 is:
fe80::6d96:1610:2097:c45%10

If you wished to ping use:
fe80::6d96:1610:2097:c45%12 where 12 is YOUR InterfaceIndex.
fe80::6d96:1610:2097:c45%10 wont get through.

To tell the full story plain fe80::6d96:1610:2097:c45 works in Windows 8

Troubleshooting IPv6 Connection Problems

Start with two reliable old commands:

• Ipconfig  (remember the /all switch).
• Ping another machine on the network.

Break the problem in to simple questions:
Is the root cause the Windows 8 machine, or the router?

• Browse from another machine on the same network.
• Check DNS settings, again compare the broken machine with one that's working.
• Ask 'what's changed lately?'
• Avoid overthink, keep it simple – try a reboot.
• Don't make it worse; for instance, don't disable IPv6, that's not the problem.

See more on Windows 8 PC Settings »

Summary of Windows 8 IPv6

IPv6 is the way to go.  To be fair, Microsoft and Windows 8 are ready, thus you can employ IPv6 out-of-the-box on your internal networks.  The challenge of running two protocol stacks will always remain while the internet sticks with IPv4.

Microsoft Windows 8 Networking Topics

• Windows 8 Overview  • Windows 8 Network Location  • Review of Network Performance Monitor

• Windows 8 Performance Monitor  • Windows 8 IPv6  • Windows 8 Metro Tile  • Windows 8 Shutdown

• Windows 8 Configuration  • Windows 8 Wireless  • SolarWinds Free Real-time Bandwidth Monitor