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[IPv6]Re: [v6ops] New draft: "The IPv6 Loopback Address Prefix"

Geoff Huston <gih902@gmail.com> Wed, 26 November 2025 00:49 UTC

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From: Geoff Huston <gih902@gmail.com>
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Date: Wed, 26 Nov 2025 11:48:23 +1100
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To: Mark Smith <markzzzsmith@gmail.com>
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CC: Warren Kumari <warren@kumari.net>, IPv6 <ipv6@ietf.org>, IPv6 Operations <v6ops@ietf.org>
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Subject: [IPv6]Re: [v6ops] New draft: "The IPv6 Loopback Address Prefix"
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Hi Mark,

I hear you, but I also observe that a prior effort to expand this designation 
in 2013 did not get beyoind a draft. This incarnation of the proposal is deliberately
more modest (even then I see David Farmer saying (paraphrased) "whoa! Way  
too much!" So we have one comment saying "too big" and another saying "too 
small"!


I'm inclined to say that the draft will keep this proposal  at a /96 for now but 
doubtless Warren and I will keep a close eye on any other comments
that have a view about the appropriate size for a loopback prefix.

But I do note:  "Those loopback interface addresses were all announced into
the routing protocol" might bne interpreted as a bit contrary to RFC 4291 
which says quite  definitively "keep loopback em to yourself" So I am not
exactly on board with a rationale that relates to a use scenario in routing
protocol that "exports" these addresses out to neighbours, if I interpret your 
description correctly.

regards,

  Geoff

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