#StackBounty: #networking #wireless-networking #router #dd-wrt #ipv6 Hosts connected to DD-WRT router running radvd get IPv6 addresses …

Bounty: 100

I’m trying to get IPv6 working on my local network. I know my ISP (Comcast) supports it because anything connected to the modem/router combo I rent from them gets assigned an IPv6 address and communicate using the protocol (can connect to ipv6.google.com and gets 20/20 on http://test-ipv6.com/).

However when I connect my own router (Netgreat WNDR3800, if it’s relevant) running DD-WRT to the Comcast modem/router combo none of the hosts can communicate over IPv6, although they get assigned IPv6 addresses in the prefix I was delegated by Comcast.

It seems to fail before it even leaves the LAN. Attempting to ping the IPv6 address of the router returns “Destination host unreachable”. My guess would be that I’m missing a route somewhere, but I am not familiar enough with IPv6 or routing to know how to test that theory or how to resolve it.

Technical details:

Router: WNDR3800 running DD-WRT v24-sp2. Its IPv6 configuration looks like this:

enter image description here

Router ifconfig:

root@DD-WRT:~# ifconfig
ath1      Link encap:Ethernet  HWaddr [redacted]
          inet6 addr: fe80::224e:7fff:fe74:13da/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:188122 errors:0 dropped:0 overruns:0 frame:0
          TX packets:227134 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:26587839 (25.3 MiB)  TX bytes:211385503 (201.5 MiB)

br0       Link encap:Ethernet  HWaddr [redacted]
          inet addr:192.168.2.1  Bcast:192.168.2.255  Mask:255.255.255.0
          inet6 addr: fe80::224e:7fff:fe74:13d8/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:190093 errors:0 dropped:0 overruns:0 frame:0
          TX packets:217213 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:0
          RX bytes:24491040 (23.3 MiB)  TX bytes:204922896 (195.4 MiB)

br0:0     Link encap:Ethernet  HWaddr [redacted]
          inet addr:169.254.255.1  Bcast:169.254.255.255  Mask:255.255.0.0
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1

eth0      Link encap:Ethernet  HWaddr [redacted]
          inet6 addr: fe80::224e:7fff:fe74:13d8/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:1989 errors:0 dropped:0 overruns:0 frame:0
          TX packets:21615 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:569599 (556.2 KiB)  TX bytes:3297349 (3.1 MiB)
          Interrupt:4

eth1      Link encap:Ethernet  HWaddr [redacted]
          inet addr:10.0.0.59  Bcast:10.0.0.255  Mask:255.255.255.0
          inet6 addr: 2601:601:XXXX:XXXX:XXXX:XXXX:XXXX:13d9/64 Scope:Global
          inet6 addr: fe80::224e:7fff:fe74:13d9/64 Scope:Link
          UP BROADCAST RUNNING MULTICAST  MTU:1500  Metric:1
          RX packets:216381 errors:0 dropped:0 overruns:0 frame:0
          TX packets:181622 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:202350364 (192.9 MiB)  TX bytes:25482727 (24.3 MiB)
          Interrupt:5

ipconfig from Windows 8.1 host connected to the router:

C:Usersseth>ipconfig

Windows IP Configuration


Wireless LAN adapter Wi-Fi:

   Connection-specific DNS Suffix  . :
   IPv6 Address. . . . . . . . . . . : 2601:601:XXXX:XXXX:XXXX:XXXX:XXXX:75c3
   Temporary IPv6 Address. . . . . . : 2601:601:XXXX:XXXX:XXXX:XXXX:XXXX:2b13
   Link-local IPv6 Address . . . . . : fe80::18b5:93d6:d9db:75c3%4
   IPv4 Address. . . . . . . . . . . : 192.168.2.100
   Subnet Mask . . . . . . . . . . . : 255.255.255.0
   Default Gateway . . . . . . . . . : 192.168.2.1

(unrelated interfaces removed from output. lo, VMWare, etc)


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