Re: Forwarding Packets With Link Local Destination Addresses

Fernando Gont <fgont@si6networks.com> Thu, 07 January 2021 21:41 UTC

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Subject: Re: Forwarding Packets With Link Local Destination Addresses
To: Ron Bonica <rbonica=40juniper.net@dmarc.ietf.org>, "6man@ietf.org" <6man@ietf.org>
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From: Fernando Gont <fgont@si6networks.com>
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Date: Thu, 7 Jan 2021 18:40:18 -0300
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Hi, Ron,

On 7/1/21 14:53, Ron Bonica wrote:
> Folks,
> 
> According to RFC 4291, “routers must not forward any packets with 
> Link-Local source or destination addresses to other links”.
> 
> I interpret this statement to include packets that contain routing 
> headers. For example, it forbids an SRv6 packet whose final segment has 
> a locator that begins with FE80.
> 
> Does everyone share this interpretation? If so, do RFC 4291 or RFC 8200 
> make this sufficiently clear?

Let me ask a different question:
Why should this be any different for a routing header? The specs still 
apply.

I'd say that the case of link-locals is probably even "worse", because 
it would mean a link-local address was included in a routing header, to 
be processed by some router elsewhere in the networks. Something that 
doesn't seem to make any sense to me.

Thanks,
-- 
Fernando Gont
SI6 Networks
e-mail: fgont@si6networks.com
PGP Fingerprint: 6666 31C6 D484 63B2 8FB1 E3C4 AE25 0D55 1D4E 7492