Subject: Question on Site local address forwarding

From: Krishna Mohan Doddappaneni <[email-masked]>
Date: Wed, 28 Nov 2001 11:24:09 -0600 (CST)

HI Guys,
If The DA of the packet is site local i would not forward the packet
outside the scope.But if the SA of the packet is site local and the DA is
global,would i forward the packet outside the site?
Thanks in Advance,
Krishna

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From: Margaret Wasserman <[email-masked]>
Date: Thu, 29 Nov 2001 09:07:38 -0500

Hi Krishna,

No, you do not forward a packet with a site local SA outside
of the scope, either.  

There is a draft available which explains the rules for the
use and forwarding of scoped addresses:

http://www.ietf.org/internet-drafts/draft-ietf-ipngwg-scoping-arch-02.txt

Margaret

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From: Brian Haberman <[email-masked]>
Date: Thu, 29 Nov 2001 07:56:00 -0500

Krishna,
     Section 9 of draft-ietf-ipngwg-scoping-arch-02.txt discusses this
very issue.  The specific text is:

       If 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, then the packet is discarded and an 
       ICMP Destination Unreachable message [RFC 2463] with Code 
       2 ("beyond scope of source address") is sent to the source 
       of the packet.

This eliminates problems in forwarding the response to this packet
when the site-local SA would become the DA.

Regards,
Brian