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

Bob Hinden <bob.hinden@gmail.com> Tue, 02 December 2025 17:52 UTC

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From: Bob Hinden <bob.hinden@gmail.com>
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Date: Tue, 02 Dec 2025 09:52:01 -0800
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To: Warren Kumari <warren@kumari.net>
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CC: Bob Hinden <bob.hinden@gmail.com>, IPv6 <ipv6@ietf.org>, Geoff Huston <gih902@gmail.com>, 6man Chairs <6man-chairs@ietf.org>
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Subject: [IPv6]Re: New draft: "The IPv6 Loopback Address Prefix"
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Warren,

Two thoughts.

Chair hat on:  I agree that this should belong to 6MAN.

Individual hat on:  The question I have is about using loopback addresses for virtual host addresses.   What was done with in IPv4 always seems to me like a “hack”.   Probably because of IPv4 limitations.   We don’t have these limitations in IPv6 and I wonder if that is the right to replicate what was done in IPv4 in IPv6.

We could leave the IPv6 loop back address alone (that is, use it for loopback), and define a new set of IPv6 virtual host addresses.   It doesn’t seem to me that it has anything to do with a loopback function.   

Further, there are a lot of possibilities for what to use for this, especially given the trend to allocate a prefix to a host.   Even without that an IPv6 node can have many addresses.

Bob



> On Dec 1, 2025, at 12:02 PM, Warren Kumari <warren@kumari.net> wrote:
> 
> [ - V6OPS, +6MAN Chairs ]
> 
> Dear 6MAN chairs,
> 
> The authors would like to request adoption of this document.
> 
> It is clear that there is still work needed before the document is ready
> for publication, but it's also clear that there is significant interest in
> the topic.
> 
> It would be helpful for the document to have a designated home - I had
> originally CCed V6OPS, and there has been significant discussion there too.