How does IPv6 subnetting work and how does it differ from IPv4 subnetting?

Posted by Michael Hampton on Server Fault See other posts from Server Fault or by Michael Hampton
Published on 2012-09-11T00:57:56Z Indexed on 2012/09/11 3:40 UTC
Read the original article Hit count: 450

Filed under:

networking

|

IPv6

|

subnet

This is a Canonical Question about IPv6 Subnetting.

Related:

How does IPv4 Subnetting Work?

I know a lot about IPv4 Subnetting, and as I prepare to (deploy|work on) an IPv6 network I need to know how much of this knowledge is transferable and what I still need to learn. IPv6 seems at first glance to be much more complex than IPv4. So I would like to know:

IPv6 is 128 bits, so why is /64 the smallest recommended subnet for hosts? Related to this:
- Why is it recommended to use /127 for point to point links between routers, and why was it recommended against in the past? Should I change existing router links to use /127?
- Why would virtual machines be provisioned with subnets smaller than /64?
- Are there other situations in which I would use a subnet smaller than /64?
Can I map directly from IPv4 subnets to IPv6 subnets?
My interfaces have several IPv6 addresses. Must the subnet be the same for all of them?
Why do I sometimes see a % rather than a / in an IPv6 address and what does it mean?
Am I wasting too many subnets? Aren't we just going to run out again?
In what other major ways is IPv6 subnetting different from IPv4 subnetting?

© Server Fault or respective owner

Related posts about networking

Networking stopped working on Ubuntu

as seen on Super User - Search for 'Super User'
I installed Ubuntu 10.04 through the Wubi installer (Funny, I installed it today and thought I would have gotten 10.10). I had a network connection and everything was working fine. I rebooted my coumputer a couple of times and then suddenly, I could not connect to the network and when I click the… >>> More
Troubles with start up defenition of networking service in Ubuntu

as seen on Super User - Search for 'Super User'
I use Ubuntu 12.04.1. I put attention that networking script starting in runlevel 0: user@comp:/etc/rc0.d$ chkconfig -l networking networking 0:on 1:off 2:off 3:off 4:off 5:off 6:off When I try to move it working to appropriate run levels I get error: user@comp:/etc/rc0… >>> More
Installing the Elgg Social Networking CMS

as seen on Internet.com - Search for 'Internet.com'
One Open Source CMS that stands out above the rest for small businesses and personal networks is the Elgg open source "social engine," which can be used to create social applications. Scott Clark shows you how to install and get started with this social networking CMS. >>> More
OAuth: Token-Based Authorization for the Social Networking Age

as seen on Internet.com - Search for 'Internet.com'
The OAuth token-based authorization system allows users to grant third-party access to their resources without sharing their usernames and passwords. It's perfect for the age of data scattered across many social networking sites. >>> More
OAuth: Token-Based Authorization for the Social Networking Age

as seen on Internet.com - Search for 'Internet.com'
The OAuth token-based authorization system allows users to grant third-party access to their resources without sharing their usernames and passwords. It's perfect for the age of data scattered across many social networking sites. >>> More

Related posts about IPv6

IPV6 auto configuration not working

as seen on Ask Ubuntu - Search for 'Ask Ubuntu'
In Windows 7, my computer can automatically get a IPV6 global address and use IPV6 network, but in Ubuntu Natty, I can't find out how to let stateless configuration work. My network is a university campus network,so I don't need tunnels. I think if one thing can silently and successfully be accomplished… >>> More
Fritz!Box IPv6-Address different than IPv6-Prefix

as seen on Server Fault - Search for 'Server Fault'
In my Fritzbox it states the following: IPv6-Adresse: 2a02:8070:600::14b6:c7******, Gültigkeit: 100465/86065s IPv6-Präfix: 2a02:8070:62c:3200::/56, Gültigkeit: 100464/86064s I am not able to connect to IPv6 Addresses from computers configured by the fritzbox, because they get an address with prefix… >>> More
Static IPv6 address advertising and IPv6 autoconfig in Debian/Ubuntu

as seen on Server Fault - Search for 'Server Fault'
I have a network that advertises IPv6 addresses through IPv6 autoconfig. To allow DNS lookups and to have fancy IP addresses, we setup "static" IPv6 addresses through /etc/network/interfaces: auto eth0 iface eth0 inet dhcp iface eth0 inet6 static address a:b:c:d:e::f netmask 64 Whenever… >>> More
HTG Explains: Are You Using IPv6 Yet? Should You Even Care?

as seen on How to geek - Search for 'How to geek'
IPv6 is extremely important for the long-term health of the Internet. But is your Internet service provider providing IPv6 connectivity yet? Does your home network support it? Should you even care if you’re using IPv6 yet? Switching from IPv4 to IPv6 will give the Internet a much larger pool… >>> More
Debian, 6rd tunnel, and connection troubles

as seen on Server Fault - Search for 'Server Fault'
Long story short I am having issues with IPv6 using a 6rd tunnel with my ISP, charter business. They offer a 6rd tunnel that I think I have properly set up, but the server doesn’t reply to every ipv6 request. When the server has the network interfaces idle with no traffic for about 10 minutes, then… >>> More