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I have a scenario, where my PC(SYSTEM1) acts as a router/packet forwarder. And i wanted to have my other PC(SYSTEM2) connected to router(R1) via SYSTEM1. If the subnet length is /48, i know it is easy to handle the routing. But i have got IPv6 /64 prefix length from the provider.

How could i setup the routing tables to allow the traffic in either ways at SYSTEM1? Or any possibility to use Host-part of IPv6 address to subnet /64.

The architecture is here,

+---------+              +----------+                 +----------+
|  Router |______________| SYSTEM 1 |_________________| SYSTEM 2 |
|   (R1)  |        (eth0)|          |(eth1)     (eth0)|          |
+---------+              +----------+                 +----------+
GW: 2001:e20:1:2::1
                      eth0: 2001:e10:1:2::100
                      eth1: 2001:e10:1:2::200          SYSTEM2

Here, i tried to ping 2001:e10:1:2::200 from 2001:e10:1:2::201, but i can not reach 2001:e10:1:2::100 (or) 2001:e10:1:2::1(Router gw).

The route entries at SYSTEM1 is something like, 2001:e10:1:2::/64 via eth0.

Please suggest me how to go ahead with this?

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Tell the ISP they screwed up and only gave you a /64, and request a /56 or /48. – Michael Hampton Mar 24 '13 at 22:22

The only way to make this work without splitting the /64 into smaller subnets (thereby losing auto configuration etc) is to either bridge the LANs on System1 or to do ND proxy on System1 so that everything on the left side of System1 thinks that everything on the right side of System1 has System1's MAC address, and vice versa. That would make them use System1 as a gateway without realising it. Same as ARP proxying in IPv4.

Without knowing which OS you run I can't tell you how to set this up.

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I am using Ubuntu 12.04 in System1(same in System2 as well). Could u tell me the steps how to do it?. Best of bridge or ND proxy. – user206993 Mar 18 '13 at 6:03
This is a good start for bridging: – Sander Steffann Mar 18 '13 at 7:46

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