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

Ted Lemon <mellon@fugue.com> Sat, 13 February 2021 22:14 UTC

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From: Ted Lemon <mellon@fugue.com>
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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)
Date: Sat, 13 Feb 2021 17:14:50 -0500
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References: <988e3743-3632-d480-72c7-ab64583d4c38@si6networks.com>
Cc: David Farmer <farmer@umn.edu>, Fred Baker <fredbaker.ietf@gmail.com>, IPv6 Operations <v6ops@ietf.org>, 6man@ietf.org
In-Reply-To: <988e3743-3632-d480-72c7-ab64583d4c38@si6networks.com>
To: Fernando Gont <fgont@si6networks.com>
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On Feb 13, 2021, at 17:08, Fernando Gont <fgont@si6networks.com> wrote:
> If a new scope was created such that scope(LL) < scope(ULA) < scope(GUA),  this rule in Dest Address selection would prefer ULAs:
> 
> 
>   Rule 8: Prefer smaller scope.
>   If Scope(DA) < Scope(DB), then prefer DA.  Similarly, if Scope(DA) >
>   Scope(DB), then prefer DB.

No, rule 6 would already have chosen the GUA. 

>> It’s perhaps worth noticing that in the presence of Happy Eyeballs and gethostbyname(), I don’t know how many applications are actually using the destination address sorting rules.
> 
> All but browsers? Or am I missing something?

Any application that doesn’t have a library that does dest addr selection is going to just pick the first address it finds, or try them all, or something like that.