Question

Understanding IPv6 address formats

Posted August 3, 2015 6.6k views
Ubuntu DigitalOcean IPv6

Hello!

Under Networking in my Droplet’s info page, I can see an entry for Public IPv6 Address, however it ends in /64. I also see a configurable range. I’m not sure which to use for the network interface settings in Ubuntu. Can I just enter one of the addresses in the range as eth0’s static IPv6 address? Can I theoretically use each of the (64?) addresses by making an entry for each in Ubuntu’s network interface config file? Would pasting in the “Public IPv6 Address” as-is work? (it ends with “/64” and seems short for an IPv6 address).

I’ve read up on DigitalOcean’s IPv6 documentation, but I remain uncertain on these few things. Your help is greatly appreciated!

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3 answers

Hello and welcome to DigitalOcean.

If you enabled IPv6 at the creation you have one IP already activated and working e.g.;

Public IPv6 Address:
2a03:b0c0:3:d0::3b:2001/64
-> Your enabled IP is 2a03:b0c0:3:d0::3b:2001

/64 means that you have a /64 Subnet https://en.wikipedia.org/wiki/Subnetwork

Configurable Address Range:
2a03:b0c0:3:d0::3b:2000 - 2a03:b0c0:3:d0::3b:200f
-> You can add these IP´s (Hexadecimal) 0-f (0,1,2,3,4,5,6,7,8,9,a,b,c,d,e,f)

To add one you need to do this e.g. (2a03:b0c0:3:d0::3b:200b)

ip -6 addr add 2a03:b0c0:3:d0::3b:200b/64 dev eth0
  • Thanks for the info! So the maximum number of IPv6 addresses we can have is 16? And even though the address under “Public IPv6 Address” ends with /64, I do NOT include that in the interface config file on Ubuntu, or in my DNS records for my domain?

@jamesspinella right, only if you want to add one Address over “ip”

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