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IPv6 for private and public usage?

Hi everyone,

I am confused in IPv6, i was research some RFC but certainly i dont knows if i choose the correct. i need to configure some cisco stuff with IPv6 and i want to know what ipv6 use for private and public.

Unique local for private (

 | 7 bits |1|  40 bits   |  16 bits  |          64 bits           |
      | Prefix |L| Global ID  | Subnet ID |        Interface ID        |


      Prefix            FC00::/7 prefix to identify Local IPv6 unicast

      L                 Set to 1 if the prefix is locally assigned.
                        Set to 0 may be defined in the future.  See
                        Section 3.2 for additional information.

      Global ID         40-bit global identifier used to create a
                        globally unique prefix.  See Section 3.2 for
                        additional information.

      Subnet ID         16-bit Subnet ID is an identifier of a subnet
                        within the site.

      Interface ID      64-bit Interface ID as defined in [ADDARCH].

Global unicast for pyblic (

 | 3 |     45 bits         |  16 bits  |       64 bits              |
    |001|global routing prefix| subnet ID |       interface ID         |

Site-Local is depreceated (

Everyone's tags (4)

Hi Jorge,

Hi Jorge,

Ask yourself why you are wanting to implement ULA in your IPv6 network. If it is because it bears a striking resemblance to RFC1918 and its functionality, and that is a design paradigm you're familiar with, then you should reconsider. Private addressing was conceived due to address scarcity, something that IPv6 does not suffer from!

If I were you, I'd use GUA throughout your network and at the very least protect it with a perimeter firewall.