No more IPv6 on my DEC740

[vincen]

Hi

I have a strange issue with my DEC 740 running OPNsense. Since 2 days and after a failure at my ISP, I have lost IPv6 connectivity. I'm running OPNsense 25.7.2.
My ISP supplies an IPv6 and a /64 IPv6. I can see on the WAN side that it gets well the /64 from ISP but nothing at all on LAN side. It doesn't even distribute a local fe... IPv6 address. What should I check to find out why it doesn't work anymore without reason ?

Thanks

Vincèn

[vincen]

Hi

Additional info if someone has an idea: my ISP confirmed my router is well working for IPv6 on WAN side so not sure what's wrong on LAN side or if it's due at recent upgrades that have quite modified applications used for DHCP as far as I undersand !

Thanks

[franco]

Try to follow this troubleshooting guide and let me know: https://docs.opnsense.org/manual/ipv6.html#basic-setup-and-troubleshooting


Cheers,
Franco

[vincen]

Try to follow this troubleshooting guide and let me know: https://docs.opnsense.org/manual/ipv6.html#basic-setup-and-troubleshooting

Hi Franco

Thanks for the link and I already tried to follow that quide but it's too general and was not helpful at all. All the more my ISP tells me I have to use DHCPv6 with PD but option doesn't exist on WAN port in my OPNsense :(

Vincèn

[franco]

Hi Vincèn,

The fundamental question from the guide is simple: does your WAN get IPv6 from the ISP? And if, yes, do your clients get IPv6 from your OPNsense?

Without the answer to this question we don't know which end has to be debugged. I'm leaning towards the WAN side but I have literally no way to know this from the information you already provided.


Cheers,
Franco

[vincen]

Hi Franco

Sorry for the late answer and thanks for your message :) Now my router doesn't get anymore an IPv6 from WAN side (it only displays a local one fe80::f690:eaff:fe00:88dd/64) and of course no IPv6 at all on LAN :(
I'm thinking as I did last time I had similar problem reset fully the router.

Thanks

Vincèn

[JamesFrisch]

Now my router doesn't get anymore an IPv6 from WAN side

Sounds like an ISP problem. Have you contacted them? What technique do they use, DHCPv6? Request the prefix over IPv4?

[franco]

> IPv6 from WAN side (it only displays a local one fe80::f690:eaff:fe00:88dd/64)

Well, the link-local can be normal. You still have not answered the question if your firewall can ping IPv6 targets...


Cheers,
Franco

[vincen]

> your firewall can ping IPv6 targets...

Not sure which firewall you are talking about but if I try to ping from Opnsense an IPv6 on Internet I get: No route to host.

Thanks
Vincèn

[franco]

Yes, so that means it's between the OPNsense and the ISP, not between OPNsense and your clients.

Now the question is if your ISP changed this or we ;) You can enable DHCPv6 debug log and see what the "dhcp6c" process offers and how successful it is.


Cheers,
Franco

[vincen]

Yes, so that means it's between the OPNsense and the ISP, not between OPNsense and your clients.

Well at fist it was between OPNsense and clients as it was still getting an IPv6 class from my ISP. After trying to fix the problem, it doesn't get anymore any IPv6 on WAN :(

Now the question is if your ISP changed this or we ;) You can enable DHCPv6 debug log and see what the "dhcp6c" process offers and how successful it is.

ISP confirmed they changed nothing and I trust them (Init7 in Switzerland). Not sure to understand what you say about DHCPv6 as it's not activated on WAN, it's only activated on LAN although not sure it should be considering that ISP gives me a class of IPv6 for my LAN.

[franco]

It's difficult to guide you through this without the proper basics mutually understood between us.

DHCPv6 here refers to the WAN IPv6 mode which you are likely using? Yes? No?


Thanks,
Franco

[vincen]

It's difficult to guide you through this without the proper basics mutually understood between us.
DHCPv6 here refers to the WAN IPv6 mode which you are likely using? Yes? No?

Thanks for your help but I'm going to reinstall device as there is clearly some issue in it regarding DHCP and IPv6. I'll let you know how it goes once reset and reconfigured ;)