IPv6 issues

[counteradditional]

G'day all,

Hoping someone can point me in the right direction, I have IPv6 configured on my opnsense install (and has been for a few months now) and has been working absolutely fine until around a week ago.

I have 4 different VLANs all with IPv6 configured on its own /64 subnet (router always at ...::1/64). Three of my VLANs appear to be working fine, however on one (internal LAN/client machines) it seems that I cannot get OPNsense to route traffic at all, pings to even the routers IP return "Destination host unreachable".

DHCPv6 enabled on this network and SLAAC too with the following config:

RA: Assisted
Router Priority: Normal
Source Address: Automatic
Advertise Default Gateway: Checked
All other options are default

This is the same config for the 3 other VLANs that are working fine.

Any chance someone else has come across this? I've checked firewall rules etc, and all is working fine.

Only issue I do know of is that my IP space isn't being advertised at the moment by a BGP session I have with a cloud provider, but this shouldn't affect internal VLAN to VLAN routing as far as I'm aware.

[Saarbremer]

Did you check the actual IPv6 configu on one of the affected clients? Do they have the network's prefix available?

Destination host unreachable sounds like there was no ICMP echo request put on the network.