Re: [v6ops] DAD again [was: draft-ietf-v6ops-host-addr-availability discussion]

"Hemant Singh (shemant)" <> Sat, 14 November 2015 18:48 UTC

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From: "Hemant Singh (shemant)" <>
To: Gert Doering <>
Thread-Topic: [v6ops] DAD again [was: draft-ietf-v6ops-host-addr-availability discussion]
Date: Sat, 14 Nov 2015 18:48:06 +0000
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Subject: Re: [v6ops] DAD again [was: draft-ietf-v6ops-host-addr-availability discussion]
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-----Original Message-----
From: Gert Doering [] 
Sent: Saturday, November 14, 2015 1:13 PM
To: Hemant Singh (shemant)
Cc: Owen DeLong;
Subject: Re: [v6ops] DAD again [was: draft-ietf-v6ops-host-addr-availability discussion]

>This, actually, is a totally meaningless example.

Not it's not since Owen ask that the lo interface is not in the same subnet at the outbound interface, so how is data forwarding working with ND if an address resolution is needed?  I proved data forwarding works.  I sure could have added to the example a log of the ND address resolution but any ND log is very copious due to NUD and thus I skipped the ND log. 

>I can send packets round the world with any source address I choose, and it has no significance for on-link NS or DAD with the *on-link* address of intermediate network segments.

>If you look more closely at your box, you'll see that it will not use the
>2004::1 source address for ND on the next-hop lan interface.

Correct.   This is what my point to Owen was.   The lo interface IPv6 address can be used to source packets out the router, and if the outbound interface has an incomplete or nonexistent entry in the neighbor cache, the outbound interfaces issues a ND address resolution and if the address resolution is completed, the packet is forwarded out.   I did issue "clear ipv6 neigh" on my router to clear the neighbor cache to force a ND address resolution.  The ND address resolution NS can use the link-local address or the global address of the outbound interface for sourcing the NS.