[ipv6hackers] IPv6 configure HomeNet with multiple subnets

Holger von Rhein ipv6hackers at lortas.de
Mon Oct 30 11:40:21 CET 2017

On Mo 2017-10-30 12:06, Mal wrote:
>Typically, your ISP will provide:
>- -a dynamic /64 IPv6 prefix for your PPP session (it will change >frequently)
>- -a static IPv6 prefix for use on your LAN, typically /56 - /64.

www.netcologne.de/ipv6 says : one /64 and additionally one /48

>Are you sure your customer-based LAN prefix is not a static assignment ?

www.netcologne.de/ipv6 says: static only if you pay for it.

my FritzBox shows:

verbunden seit 29.10.2017, 18:54 Uhr, NetCologne / NetAachen VDSL-Anschluss,
IPv6-Adresse: 2001:4dd0:af16:WWWW:MMMM:MMMM:MMMM:MMMM, Gültigkeit: 2591748/604548s,
IPv6-Präfix: 2001:4dd5:KKKK::/48, Gültigkeit: 77543/77543s

And after initiating a re-connect:

verbunden seit 30.10.2017, 10:52 Uhr, NetCologne / NetAachen VDSL-Anschluss,
IPv6-Adresse: 2001:4dd0:af16:VVVV:MMMM:MMMM:MMMM:MMMM, Gültigkeit: 2591904/604704s,
IPv6-Präfix: 2001:4dd5:LLLL::/48, Gültigkeit: 89873/89873s

where "MMMM:MMMM:MMMM:MMMM" is equal after re-connect.

The values of WWWW, KKKK and LLLL are all different.

so, yes I am pretty sure that my customer-based LAN prefix is not a static assignment.


On Mo 2017-10-30 06:51, Marc wrote:
>I don't think there is a dhcpv6 or RA daemon that handles getting the range and distributing it locally, but you might be lucky by searching the open source directory of dsl router vendors like avm etc

After continuing research I found the dhcpv6 relay functionality: page 17 section 4.2 in http://klub.com.pl/dhcpv6/doc/dibbler-user.pdf
This looks promising. But I have still no clue how to inform the isp-router (fritzbox) that my connected linux-gateway acts as router for 2001:4dd5:LLLL::/48

My linux-gateway gets the following IPv6 address: 2001:4dd5:LLLL:0:NNNN:NNNN:NNNN:NNNN/64 (scope global mngtmpaddr dynamic)

so the isp-router already use only a part (/64) of the /48 Range as link local network.

>Otherwise just roll your own, should be pretty easy when using RA. When the network range changes you deprecate the old one (lifetime 0) and send the new one.

Yea, I hoped not need to develop my own script/daemon, because there is some ICMPv6 mechanism I just do not know right now.

But still, if I go for developing my own solution, is there an ICMPv6 message that I can use to say: "Hey guys on this side, I know I am not your default gateway, but if you have packages for 2001:4dd5:LLLL::/48 you need to use me as hop."


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