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

Michael Richardson <mcr+ietf@sandelman.ca> Wed, 06 January 2021 17:11 UTC

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From: Michael Richardson <mcr+ietf@sandelman.ca>
To: Fernando Gont <fgont@si6networks.com>
cc: Gert Doering <gert@space.net>, IPv6 Operations <v6ops@ietf.org>, ipv6@ietf.org
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Date: Wed, 06 Jan 2021 12:11:32 -0500
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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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Fernando Gont <fgont@si6networks.com> wrote:
    > On 6/1/21 13:26, Gert Doering wrote:
    >> HI,
    >>
    >> On Wed, Jan 06, 2021 at 12:42:13PM -0300, Fernando Gont wrote:
    >>> And, as noted, there are concrete implications:
    >>> RFC4007 says ULAs are non-global, RFC4193 says that ULAs are global, and
    >>> a Python library says ULAs are non-global. I don't think we want that.
    >>
    >> On a tangent, I wonder why this is relevant at all.
    >>
    >> Why should applications, or anything that is not an admin, care if an
    >> address is a ULA or a GUA?

    > I can report on my own case:

    > I have Raspberry Pis that deploy here and there. In order to be able to
    > access them, they use dynamic DNS to post their addresses on their DNS.
    > If I don't look at the properties of the addresses, then I end up puting crap
    > on the DNS. One straightforward consequence is that many apps that don't do
    > Happy Eyeballs end up having an insane connection-establishment period, if
    > they happen to try the unusable addresses first.

    > So "find all your IPv6 addresses and post them to the DNS" doesn't work.

And, yet, for the case where some device is doing dynamic DNS update to a DNS
server that is within some ULA scope, posting the ULA to the DNS is actually
correct.
But, it's hard to know that without knowing what clients are expected to connect.

--
Michael Richardson <mcr+IETF@sandelman.ca>   . o O ( IPv6 IøT consulting )
           Sandelman Software Works Inc, Ottawa and Worldwide