I have two routers on my network. The first router uses SLAAC and is connected to the internet where my ISP provides a /56 IPv6 subnet. The second router is running OpenWRT (latest stable).
The WAN6 interface on the second router seems to be working as it gets a good IPv6 address and ping6 google.com (from the router) works. But the LAN interface is getting an address that starts with f and the clients connected to it have no IPv6 internet connectivity.
The firewall rules allow DHCPv6 to/from WAN.
The WAN6 interface settings:
Protocol: DHCPv6 client
Request IPv6-address: try
Request IPv6-prefix of length: 64
The LAN interface settings:
IPv6 assignment length: 64
IPv6 assignment hint:
Router Advertisement-Service: server mode
DHCPv6-Service: server mode
DHCPv6-Mode: stateless + stateful
I've tried setting various combinations of options for the LAN interface DHCP server but I'm unable to get a working IPv6 connection. What am I missing?
If you are sure that your ISP provides a 56 subnet, I would try on the WAN6 interface a different setting. I use in "Request IPv6-prefix of length" automatic and this works fine. If not, then try e.g. 62. 64 is not enough for a IPv6-PD prefix delegation as far as I know. With a setup like this, I can then use on the LAN and my separate WIFI interface own 64 subnets.
Sometimes I had to restart the interfaces WAN6 and LAN to get the IPv6-PD working and it can take 30 seconds.
Sadly IPv6-PD is not as easy as it should be!!! The cable router that I received from Vodafone was not capable of doing IPv6-PD even though it got a 56 suffix! I do have now a own Fritz!Box 6591 as a cable router, it didn't activate IPv6-PD delegation by default, but after doing the setup it works now.
If your second router doesn't get the IPv6-PD address on WAN6, then I assume your first router might have an issue.
I think WAN6 is getting the IPv6-PD address but I may not be understanding correctly.
The first router is configured with several VLANs and it assigns them each a prefix-id. For example prefix-id 10 for VLAN 10, prefix-id 20 for VLAN 20, etc. The OpenWrt router is connected to one of these VLANs and I can see that the IPv6 address that it gets on the WAN6 interface has the correct prefix-id in it so I'm assuming DHCPv6-PD and SLAAC are working but that may not be a valid test of that.
By the way, all hosts that are connected to the first router work with IPv6. It's just the LAN interface on the OpenWrt router that doesn't seem to be working.
Well, my WAN6 interface shows the following information on the second router (some characters are replaced with x): Protocol: DHCPv6 client Uptime: 1h 26m 39s MAC: 30:23:xx:xx:xx:xx RX: 340.74 MB (307783 Pkts.) TX: 19.01 MB (126069 Pkts.) IPv6: 2a02:8070:xxx:xxxx:xxxx:xxxx:xxxx:xxxx/128 IPv6-PD: 2a02:8070:xxxx:xxxx::/62
If you just get one line with IPv6, then this is not enough for prefix delegation.
I'm not an expert, but in my experience you need the IPv6-PD address to get a correctly functioning IPv6 LAN interface, it looks like this: Protocol: Static address Uptime: 22h 35m 20s MAC: xx:xx:xx:xx:xx:xx RX: 32.26 GB (14283107 Pkts.) TX: 2.07 GB (15649279 Pkts.) IPv4: 192.168.1.1/24 IPv6: 2a02:8070:xxxx:xxxx::1/64 IPv6: fdea:xxx:xxxx::1/64
I can't tell you how the relay mode would work with IPv6.