IPv6 no more working on DEC740

[vincen]

Hi

I have a DEC740 that I use since nearly 3 years now with my Init7 fiber 10G connection and it worked great. I have not used it during few months as I was testing an other router.
Now I install it back and do all updates, updating to 24.7.10. Unhappy now the IPv6 is no more working. In Dashboard instead of listing the /48 he should get from ISP it lists a local IP: fe80::200:f7ff:fef7:256
ISP has confirmed that my router requests well an IPv6 class but it doesn't show up in OPNSense and also it doesn't distribute anymore any IPv6 in LAN :(
What should I check or investigate ? It has been a long time I didn't "play" with OPNSense.

Thanks

Vincèn

[vincen]

Hi

No one on this ?

Thanks

Vincèn

[newsense]

Chances are Franco will see this thread later today, assuming he might be busy for a bit with 24.7.11 which is due in a few hours.

In the meantime if you could have a look at the logs and post it here that would definitely speed up the diagnosing and potential fix required for your ISP

[franco]

Check the WAN overview details first. If you set to only request a prefix you only see a link-local present. The PD can still be given by the ISP and offered to the LANs...

[vincen]

Check the WAN overview details first. If you set to only request a prefix you only see a link-local present. The PD can still be given by the ISP and offered to the LANs...

Sorry for the late answer and thanks for your help. As far as I know it gets well the IPv6 class my ISP gives me (tech support confirmed me that my router is getting well the class from their IPv6 DHCP. In lobby of my OPNSense it lists that:
fe80::f690:eaff:fe00:88dd%ax1/64
but on LAN it lists that: 2a02:169:280e:0:5a9c:fcff:fe10:797c/64 which is well the class I got from my ISP. Question is: why it doesn't forward anymore DHCP v6 requests properly from LAN to WAN as it was doing in the past ?

Thanks

[franco]

Hi,

It looks like DHCPv6 to your LAN works as intended, which means take a look at step 2 in https://docs.opnsense.org/manual/ipv6.html#basic-setup-and-troubleshooting


Cheers,
Franco

[patient0]

I have a DEC740 that I use since nearly 3 years now with my Init7 fiber 10G connection and it worked great. I have not used it during few months as I was testing an other router.

I'm late to the show (I'm with Init7, too): Init7 uses the MAC address of the WAN network interface to assign the IPv6 prefix (so they told me). Since you did use another router for some time, are you spoofing the MAC address? Even if not, it should still work but you may get a different prefix.

Dashboard instead of listing the /48 he should get from ISP it lists a local IP: fe80::200:f7ff:fef7:256

fe80::200:f7ff:fef7:256 is the IPv6 gateway of Init7, that is the same I got, so that is correct (as the gateway). What is missing then is the IPv6 address for the WAN interface itself. The IPv6 address for the WAN interface will not be within your prefix, mine starts with 2a02:168:.... and the prefix starts with 2a02:169:...

Please make sure in the WAN interface configuration "Request prefix only" is not checked.

Btw: It's usually a good idea to not put your public IP(s) on display, instead either replace it with something made up like 2a02:aaaa:bbbb:cccc:... or mask some of the bits like 2a02:168:xxxx:xxx:5a9c:fcff:fe10:797c/64. IPv6 that start with "fe80::" are not public and are ok to post.

[franco]

If you don't set to request an address on WAN that can be normal with the link-local only. Operationally, it doesn't make a difference for clients.


Cheers,
Franco

[patient0]

If you don't set to request an address on WAN that can be normal with the link-local only. Operationally, it doesn't make a difference for clients.

It should work then from LAN when the correct gateway is received from upstream, yes?

[franco]

Yes, the gateway comes from SLAAC and there should also be a SLAAC address on WAN, but we don't show it because it's not dependable. The routing works via link-local. When you get a GUA on a tracking LAN that's already fair to assume that connectivity to the internet works from the OPNsense. Then the only question is if radvd or dhcpv6 will offer the LAN GUA prefix (/64) to the clients.


Cheers,
Franco

[patient0]

Thanks you franco for clarifing it, *thump-up* :)

Then the only question is if radvd or dhcpv6 will offer the LAN GUA prefix (/64) to the clients.

That's the confusing bit, he wrote that he gets what looks a correct (Init7)/64 on LAN, tracking seems to work.

[franco]

I'm focusing on the bit here:

> and also it doesn't distribute anymore any IPv6 in LAN :(

Which coupled with the reply:

> but on LAN it lists that: 2a02:169:280e:0:5a9c:fcff:fe10:797c/64

means that only clients have issues at this point.

But either way the troubleshooting steps are in the documentation that I posted earlier for both step 1 and step 2. It's easy to follow this list and pinpoint the issue.