[SOLVED] IPv6 Routing issues with subnets

stekahelo · 06-17-2017, 10:20 AM

Since the Sixxs tunnelbrocker went down I would like to use IPv6 from my ISP (German Telekom). The Telekom provides a /56 prefix which I want to subnet and use in my local LANs.

Code:

                 Internet
                    ^
                    |
                    v
                 ppp100
               Router (R1)
         eth0.103 eth0.102 eth0.104
             /     |        \
            /      |         \
           /      eth1        \
        Guests  Gentoo (R2)   DMZ
                  eth0
                   |
                   | 
                  LAN --> Notebook

I get a IPv6 address for the ppp100-device. Also I query the /56 prefix, but I use only a /60.

These are the IPs and routes on R1:

Code:

IPs
ppp100 : 2003:d0:33bf:275b:36ee:995e:6dd7:1a2b/64
eth0.102 : 2003:d0:33f8:5000::1/60
eth0.102 : fe80::1/64

Routes
2003:d0:33bf:275b::/64 dev ppp100
2003:d0:33f8:5000::/60 dev eth0.102
default via fe80::100:100:3e9b:f606 dev ppp100

And on R2 I use the following setup:

Code:

eth1 : 2003:d0:33f8:5000:280:c9ff:fe00:3ef/64
eth0 : 2003:d0:33f8:500e::1/64
eth0 : fe80::1/64

Routes
2003:d0:33f8:5000::/64 dev eth1
2003:d0:33f8:500e::/64 dev eth0
default via fe80::1 dev eth1

On R2 is dnsmasq running to advertise the net. So my notebook gets following settings:

Code:

IPs
eth0 : 2003:d0:33f8:500e:11fc:60db:35f2:5582/64

Routes:
2003:d0:33f8:500e::/64 dev eth0
default via fe80::1 dev eth0

I can ping IPv6 hosts in the internet from R1 and R2. Also I can ping the IPs of R1 and R2 from a dedicated server

Code:

ping6 2003:d0:33bf:275b:36ee:995e:6dd7:1a2b
ping6 2003:d0:33f8:5000::1
and
ping6 2003:d0:33f8:5000:280:c9ff:fe00:3ef
works

I could not reach any host of the ..:500e:: network, also ping 2003:d0:33f8:500e::1 from R1 does not work. I could not ping any IPv6 address from the local LAN (notebook) after eth1, too. It seems like routing on R2 is disabled, but it is enabled:

Code:

cat /proc/sys/net/ipv6/conf/{all,eth0,eth1}/forwarding
1
1
1

If I run tcpdump (tcpdump -n -vv -i eth0.102 ip6) on R1 while ping an internet host from the notebook, I see that there are queries (neighbor solicitation) to get the sending host, but there is no response:

Code:

ip -6 neigh
...
2003:d0:33f8:500e:11fc:60db:35f2:5582 dev eth0.102  FAILED

There is no firewall on R2 running and on R1 it is a very basic one.

It would be very nice if someone could give me a hint

stekahelo · 06-18-2017, 05:14 AM

Hi,

I've found my mistake: I did not specify a gateway for the routed networks on R1 to R2.
Now it works as expected.