Re: [v6ops] DAD again [was: draft-ietf-v6ops-host-addr-availability discussion]
Philip Homburg <pch-v6ops-3@u-1.phicoh.com> Tue, 03 November 2015 23:07 UTC
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In-reply-to: Your message of "Wed, 4 Nov 2015 10:47:25 +1300 ." <56392B6D.8030703@gmail.com>
Date: Wed, 04 Nov 2015 00:06:53 +0100
Archived-At: <http://mailarchive.ietf.org/arch/msg/v6ops/uJ0XRFO-zACC900pZ1VlpvaNcVI>
Subject: Re: [v6ops] DAD again [was: draft-ietf-v6ops-host-addr-availability discussion]
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> > Also, what if node B in fact did do DAD and A heard it? What is to stop > > A from configuring a duplicate address and trying to use it just to mess > > up the legitimate operation of node B? > > Nothing. That, I think, is why the RFCs make DAD mandatory. There are a few things something I don't understand in this discussion. Suppose we have a router with one upstream ethernet interface and a couple of downstream interfaces. The upstream interface does not have any addresses assigned other than link local. The router receives a prefix through DHCPv6 and assigns a number of /64 prefixes to the downstream interfaces. Two things should be obvious: - the router is not going to perform DAD on addresses used by hosts on its downstream interfaces - other routers on the upstream interface are not going to use ND on addresses covered by the prefix, they will use the link local address of the router instead. No we replace the router by a host. The host receives a prefix using DHCPv6 PD and starts using it. Why would the host perform DAD on addresses covered by the delegated prefix when a router would not do this? Why would routers try to perform ND on addresses covered by the prefix instead sending traffic to the link local address? There might be a problem though. Routers take part in a routing protocol. So it should be obvious to all routers how to forward traffic to a delegated prefix. When prefix delegation happens over a point-to-point link then, 'the other side' is also clearly defined. So a host could receive a prefix and it would work. In the case of ethernet, if a host receives a prefix over DHCPv6 PD, then a router connected to the host has to create a routing entry that forwards the prefix to link local address of the host (as found in the DHCPv6 requests). How is the delegating router supposed to know this? If we have special treatment for hosts, then another option would be to logically assign the addresses to the ethernet interface, perform DAD and have other nodes perform ND. But I have no idea how that should be signalled. Manual configuration on the delegating router? Consistency with CPE behavior suggests that hosts should never assign addresses to the (upstream) link and therefor not perform DAD on those addresses.
- [v6ops] draft-ietf-v6ops-host-addr-availability d… Fred Baker (fred)
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Alexandre Petrescu
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Lorenzo Colitti
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Lorenzo Colitti
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Brian E Carpenter
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… David Farmer
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… David Farmer
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Lorenzo Colitti
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Lorenzo Colitti
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Brian E Carpenter
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Alexandre Petrescu
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Lorenzo Colitti
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Alexandre Petrescu
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Lorenzo Colitti
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Alexandre Petrescu
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… David Farmer
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Lorenzo Colitti
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… David Farmer
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Lorenzo Colitti
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… David Farmer
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Alexandre Petrescu
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Alexandre Petrescu
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- [v6ops] DAD again [was: draft-ietf-v6ops-host-add… Brian E Carpenter
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Templin, Fred L
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Philip Homburg
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… Templin, Fred L
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Mukom Akong T.
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Templin, Fred L
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… 神明達哉
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Lorenzo Colitti
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Alexandre Petrescu
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Alexandre Petrescu
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Gert Doering
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Gert Doering
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Owen DeLong
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Owen DeLong
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Owen DeLong
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Owen DeLong
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Owen DeLong
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Gert Doering
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Gert Doering
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Gert Doering
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Owen DeLong
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Templin, Fred L
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Owen DeLong
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Templin, Fred L
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Hemant Singh (shemant)
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Owen DeLong
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Owen DeLong
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Brian E Carpenter
- Re: [v6ops] DAD again [was: draft-ietf-v6ops-host… Templin, Fred L
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… David Schinazi
- Re: [v6ops] draft-ietf-v6ops-host-addr-availabili… David Farmer