CCNA IPv6 Address Types

Question 1

Why do I use the 2001:db8:: /32 range in these videos?

This range has been reserved for documentation and demonstration purposes only. This means it’s never assigned to anyone to use on a live network.

This is important because I wouldn’t want to be using anyone’s real details in videos that are available to the public!

Question 2

Can we use NAT to translate one IPv6 address to another IPv6 address?

Technically, yes. There is a technology called NAT66, which will translate one IPv6 address to another.

However, it’s not intended to be used like NAT for IPv4 is. It’s meant to be there as a way to work around IP conflicts and things like this. In reality, it should be avoided when possible.

It can be a big shift in thinking, but we need to get comfortable with the idea that we don’t use NAT with IPv6.

Question 3

If you use a unique local range in your network, why should you try to make your prefix unique?

If your company ever merges with another or connects to a partner, and you have the same unique local IP space, you won’t be able to route between these two networks. Networks need to be unique to enable routing.

This isn’t an issue with global unicast IPs, as they’re guaranteed unique when they’re allocated to you. This is probably just another good reason to use global unicast IPs instead of unique local IPs.

Question 4

Which IPv6 addresses are not routable?

Link-local IPs are not routable at all

Unique local addresses are routable within your private network, but not routable on the internet.

Question 5

Find the first and last subnets that we can use from these networks (assuming we’re allocating /64’s):

  • 2001:db8:179:: /48
  • 2001:db8:179:: /56
  • 2001:db8:179:: /57
  • 2001:db8:179:: /58
  • 2001:db8:179:0:: – 2001:db8:179:ffff::
  • 2001:db8:179:0:: – 2001:db8:179:ff::
  • 2001:db8:179:0:: – 2001:db8:179:7f::
  • 2001:db8:179:0:: – 2001:db8:179:3f::