[IPv6][Errata Rejected] RFC4443 (6153)

RFC Errata System <rfc-editor@rfc-editor.org> Fri, 17 October 2025 04:20 UTC

To: ximaera@gmail.com, aconta@txc.com, mukesh.gupta@tropos.com
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Date: Thu, 16 Oct 2025 21:20:56 -0700
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Subject: [IPv6][Errata Rejected] RFC4443 (6153)
Archived-At: <https://mailarchive.ietf.org/arch/msg/ipv6/yCRyNCAlrHo4Hf24p-vlpYrqAT4>

The following errata report has been rejected for RFC4443,
"Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification".

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You may review the report below and at:
https://www.rfc-editor.org/errata/eid6153

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Status: Rejected
Type: Technical

Reported by: Töma Gavrichenkov <ximaera@gmail.com>
Date Reported: 2020-05-01
Rejected by: Erik Kline (IESG)

Section: 3.1

Original Text
-------------
3.1. Destination Unreachable Message

[..]

If the reason for the failure to deliver is that the destination is
beyond the scope of the source address, the Code field is set to 2.
This condition can occur only when the scope of the source address is
smaller than the scope of the destination address (e.g., when a
packet has a link-local source address and a global-scope destination
address) and the packet cannot be delivered to the destination
without leaving the scope of the source address.

Corrected Text
--------------
3.1. Destination Unreachable Message

[..]

If the reason for the failure to deliver is that the destination is
beyond the scope zone of the source address, the Code field is set to
2. The scope zone of the destination address is determined by the
scope of the address and arrival interface of the packet, as specified
in [IPv6-SCOPE, Section 9]. Similarly, the scope zone of the source
address is determined by the scope of the address and arrival
interface of the packet. This condition can occur only when
transmitting the packet on the chosen next-hop interface would cause
the packet to leave the zone of the source address, i.e., cross a zone
boundary of the scope of the source address.

7.1. Normative References

[..]

[IPv6-SCOPE] Deering, S., Haberman, B., Jinmei, T., Nordmark, E.,
and B. Zill, "IPv6 Scoped Address Architecture", RFC
4007, March 2005.

Notes
-----
https://tools.ietf.org/html/rfc4007#section-9

Scope zone is not scope.

Consider a case when the source IP is link-local and the destination is global, yet the routing happens in the same VLAN. Per RFC 4007, the packet should be transmitted; however, RFC 4443 allows for an ambiguity which is already causing vendors to reject packets in this case.
--VERIFIER NOTES--
I was tempted to mark this HFDU, since it seems like there is always the opportunity to improve clarity around text that deals with IPv6 scope concepts.

However, I'm not sure this specific text is an improvement and some discussion on the mailing list did not seem to come to any consensus as to what should be done. See also:

https://mailarchive.ietf.org/arch/msg/ipv6/pkRo2Bt4hHu9PFJf2BtYPVn4sJk/

and preceding messages.

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RFC4443 (draft-ietf-ipngwg-icmp-v3-07)
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Title : Internet Control Message Protocol (ICMPv6) for the Internet Protocol Version 6 (IPv6) Specification
Publication Date : March 2006
Author(s) : A. Conta, S. Deering, M. Gupta, Ed.
Category : DRAFT STANDARD
Source : IP Version 6 Working Group
Stream : IETF
Verifying Party : IESG

[IPv6][Errata Rejected] RFC4443 (6153) RFC Errata System