Solved How to enable IPv6 on an interface?

[grogi]

How to enable IPv6 on particular interface? ip a show dev eth0 shows only inet addresses, no inet6, not even link-local fe80 one. Trying to add one returns an error.

#> ip -6 address add fe80::1 dev eth0
RTNETLINK answers: Permission denied

Other interfaces, such as the bridge br0, or even those that are part of the bridge (eth1, eth2, vlan1) all have the link-local address.

It's RT-AC68u running Merlin 386.7_2 if that makes any difference.

 

[ColinTaylor]

Other interfaces, such as the bridge br0, or even those that are part of the bridge (eth1, eth2, vlan1) all have the link-local address.

Are you saying that you have enabled IPv6 in the GUI but your WAN interface doesn't have a IPv6 address? Are you using a 6in4 tunnel?

 

[grogi]

Thanks Colin, that's my setup. I have the 6in4 tunnel configred and successfully established. However, on the WAN side I have some other ULA networks I want to route to.

Once the interface is ipv6 capable, I can deal with manually setting up the routing table through one of the custom scripts. Unfortunately the kernel does not allow it at the moment. The sysctrl doesn't exist in those routers, so I am lost on how to enable it.

 

[ColinTaylor]

Not really my area of knowledge as I don't use IPv6, but you might need to play with these settings:

# cat /proc/sys/net/ipv6/conf/default/disable_ipv6
1
# cat /proc/sys/net/ipv6/conf/eth0/disable_ipv6
1
# cat /proc/sys/net/ipv6/conf/all/disable_ipv6
1

So maybe:

echo 0 > /proc/sys/net/ipv6/conf/eth0/disable_ipv6

ip -6 addr add 2001:0db8:0:f101::1/64 dev eth0

UPDATE: Seems to work on my RT-AX86U. In fact you don't even need to issue the ip -6 command if you only want a link local address.

# echo 0 > /proc/sys/net/ipv6/conf/eth0/disable_ipv6
# ifconfig eth0
eth0      Link encap:Ethernet  HWaddr 30:5A:3A:C7:8A:20
          inet addr:80.7.xxx.xxx  Bcast:80.7.xxx.255  Mask:255.255.252.0
          inet6 addr: fe80::325a:3aff:fec7:8a20/64 Scope:Link
          UP BROADCAST RUNNING ALLMULTI MULTICAST  MTU:1500  Metric:1
          RX packets:60965808 errors:0 dropped:0 overruns:0 frame:0
          TX packets:14426298 errors:0 dropped:0 overruns:0 carrier:0
          collisions:0 txqueuelen:1000
          RX bytes:77233976999 (71.9 GiB)  TX bytes:1764947211 (1.6 GiB)

 

[grogi]

Fantastic, exactly what I needed. Works here too!