Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)

Ted Lemon <> Sat, 13 February 2021 19:32 UTC

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From: Ted Lemon <>
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Date: Sat, 13 Feb 2021 14:32:10 -0500
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Cc: Fernando Gont <>, Fred Baker <>, IPv6 Operations <>, "" <>
To: David Farmer <>
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Subject: Re: [v6ops] Scope of Unique Local IPv6 Unicast Addresses (Fwd: New Version Notification for draft-gont-6man-ipv6-ula-scope-00.txt)
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On Feb 13, 2021, at 2:25 PM, David Farmer <> wrote:
> Wait a minute! It doesn't say SOME addresses in the global scope are globally unique, it says ALL addresses in the global scope are globally unique. Unless each and every ULA address is globally unique, then ULA can't be global scope.
> And by what definition of global scope are the Local-Use IPv4/IPv6 Translation Prefix, the Discard-Only Prefix, and the IPv6 Benchmarking Prefix global scope?

I think we agreed that RFC 4007 makes some statements that seem incomplete or inapplicable to the present-day networks we all work with. One way to fix it is to add more scopes. Another way is to tweak the definition of the described scopes.

The problem with things like “admin scope” is that it doesn’t help me. Suppose an address is “admin scope.” Okay, how does my behavior change? Can you clearly state a rule that describes what my behavior should be?

If not, I claim it’s useless to define that scope.

Of course “my” could mean end systems, or routers, or users, or administrators, so that’s another terminology discussion to have…

So what I think “global scope” means is “there isn’t some context in which, by definition, this address is invalid.”