6rd configuration on openWRT 19.07


I'm trying to configure 6rd protocol on openWRT 19.07.1 to get ipv6 from my french provider Free on a FTTH link.

My set up is:
ISP Fiber -> TP-Link MC220L -> Netgear R7800 running openWRT 19.07.1

First let's say I have ipv4 configuration working (dhcp client on vlan 836 gives me my ipv4 ip) and internet reachable.

Now, my ISP gives an ipv6 through 6rd protocol.

  1. I know my ipv6 prefix (can get it on my ISP web site or on its official modem) : 2a01:e35:xxxx:xxx0::/64
  2. I know my ipv4 ip address (same, either from the ISP web site or the modem) 82.nnn.nnn.nnn
  3. I get my ipv4 peer address from running a tcpdump on my openWRT and pinging my ipv6 preffix from an online ping6 website on internet
    From http://ipv6now.com.au/pingme.php pinging 2a01:e35:xxxx:xxx0::1
    I see on my openWRT:
    root@r7800:~# tcpdump -i eth0.836 proto 41
    16:05:33.378984 IP > ipv4.reverse.dns.alias: IP6 xxxx:xxxx::xxxx:xxxx:xxxx > 2a01:e35:xxxx:xxx0::1: ICMP6, echo request, seq 1, length 64
    So my peeraddr is (seems everyone gets the same from my ISP)

Looking at the doc on https://openwrt.org/docs/guide-user/network/ipv6_ipv4_transitioning#rd_tunnel_isp-provided_ipv6_transition
It seems I have everything needed!

I install 6rd protocol
opkg install 6rd

Then try to configure my wan6 interface with 6rd protocol
config interface 'wan6'
option ifname 'eth0.836'
option auto '0'
option proto '6rd'
option peeraddr ''
option ip6prefix '2a01:e35:xxxx:xxx0::/64'

But when I try to start the wan6 interface, all I get are errors:
Fri Feb 28 17:15:58 2020 daemon.notice netifd: Interface 'wan6' is setting up now
Fri Feb 28 17:15:59 2020 daemon.notice netifd: wan6 (26049): Command failed: Unknown error
Fri Feb 28 17:15:59 2020 daemon.notice netifd: Interface 'wan6' is now down

Any idea please?

Ok, managed to obtain my ipv6 and not getting the errors!

It's far easier than what I thought!

config interface 'wan6'
option proto '6rd'
option peeraddr ''
option ip6prefixlen '28'
option ip6prefix '2a01:e30::'

Ipv6 preffix is obtained from https://alephs.org/6rdcalc.html directly.
My own ipv6 preffix (the one I see on my ISP web site is calculated from my ipv4 address and that preffix)

Now, all I have to find is how to get ipv6 networking working on my lan!

In most cases it should work by default.
In any case read the documentation for setting it up to your needs.