> On 27 June 2021, at 14:07, Brian E Carpenter <[email protected]> > wrote: > > Please don't look at ancient drafts. Look at the homenet architecture RFC: > https://www.rfc-editor.org/info/rfc7368
I went looking when I saw the date on the draft and found the RFC. > > Definitively, using any prefix longer than /64 *will not work*. The /64 has > been carved in stone for many years; that's *why* you get a /48 or /56 > from the ISP. Unfortunately there are ISPs that are giving out /64 or even smaller. The claim is that is only temporary, but no indication of when that would stop. > >> The B router receives the prefix via SLAAC and creates its own EUI-64 >> address. However, that router needs to create a smaller subnet... > > That doesn't work. B needs to get its own /64 prefix(es) from A via DHCPv6-PD > (https://www.rfc-editor.org/info/rfc8415). That's what DHCPv6-PD is for. So A > will indeed need to be a DHCPv6 server on its downstream interfaces. The issue is though how does the server get the prefix the client received? I suspect the script and restart of the server is probably the only way at this tim. > > If you run OpenWrt on A, this is apparently supported. See > https://openwrt.org/docs/guide-user/network/ipv6/dhcp6c#example. But I have > no experience with that. > > Regards > Brian Carpenter > > On 28-Jun-21 08:32, Doug Hardie wrote: >> >> -- Doug >> >>> On 27 June 2021, at 12:41, Michael Chang <[email protected] >>> <mailto:[email protected]>> wrote: >>> >>> If you actually want that topology, I think in practice the downstream > router (B) must be at least a /64; if you got a /48 then I think you can set > up A with /56s, which it can use to sub-allocate a /64 to B. >>> >>> https://tools.ietf.org/id/draft-ietf-homenet-arch-01.html >>> <https://tools.ietf.org/id/draft-ietf-homenet-arch-01.html> >>> >>> The config in section 7.2 of >>> https://wiki.archlinux.org/title/IPv6#Prefix_delegation_(DHCPv6-PD) >>> <https://wiki.archlinux.org/title/IPv6#Prefix_delegation_(DHCPv6-PD)> might >>> be what you're looking for? (See the note about `sla-len`.) >> >> The addresses could be done that way. However, the issue still remains, how >> does router B distribute the prefix? Is using a dual dhcp6c - dhcp6s the >> way to go and how does dhcp6s get the prefix from dhcp6c? >> >>> >>> >>> On Sun, Jun 27, 2021 at 12:05 PM Kristian McColm >>> <[email protected] <mailto:[email protected]>> >>> wrote: >>> >>> RFC 5375 advises against prefixes longer than /64. >>> >>> https://datatracker.ietf.org/doc/html/rfc5375#appendix-B.2 >>> <https://datatracker.ietf.org/doc/html/rfc5375#appendix-B.2> >>> >>> A /48 gives you 65535 /64’s, why not use some of them? >>> >>> >>> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ >>> *From:* [email protected] >>> <mailto:[email protected]> >>> <[email protected] >>> <mailto:[email protected]>> on behalf of Doug Hardie >>> <[email protected] <mailto:[email protected]>> >>> *Sent:* Sunday, June 27, 2021 2:54:01 PM >>> *To:* [email protected] <mailto:[email protected]> > <[email protected] <mailto:[email protected]>> >>> *Subject:* Prefix delegation to sub nets >>> >>> I am trying to setup an IPv6 environment. There is a primary > router (A) that receives a /48 prefix via DHCP6 from the ISP. That router > configures itself properly via dhcp6c. It also creates 2 LAN /64 prefixes > and creates EUI-64 addresses on the two LAN interfaces. One of those > interfaces is connected to a second router (B), among other devices. The B > router receives the prefix via SLAAC and creates its own > EUI-64 address. However, that router needs to create a smaller subnet, /72, > and distribute it to the devices on that LAN. I have not been able to figure > out how to make that happen. >>> >>> Clearly, manual configuration would work, but the prefix received from >>> the ISP can change which would raise havoc with the network. I > suspect that dhcp6s needto be run alongside dhcp6c on router B and then the > other devices run dhcp6c. However, I don't see how to get the prefix that > dhcp6c receives on router B to the dhcp6s process on router B. I believe I > am missing something, but haven't been able to find it. Thanks, >>> >>> -- Doug >>> >>> >>> >>> >>> >>> >>> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ >>> This communication is confidential. We only send and receive email > on the basis of the terms set out at www.rogers.com/web/content/emailnotice > <http://www.rogers.com/web/content/emailnotice> >>> >>> >>> >>> Ce message est confidentiel. Notre transmission et réception de >>> courriels se fait strictement suivant les modalités énoncées dans l’avis >>> publié à www.rogers.com/aviscourriel <http://www.rogers.com/aviscourriel> >>> >>> ------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------ >>> >>> >>> >>> -- >>> Michael Chang >> >
