Unfortunately, it does not work for me on 25.03-BETA. The setting has not changed behaviour - i have tried a reboot after adding the setting into system->advanced>system tunables.
I did try this setting weeks ago, but since it made no difference I disgarded it.
I still need to add the static NDP entry, even with this setting.
I wonder if this setting is no longer working on 25.03-BETA. However, that NDP entry should not be going stale for 24 hours anyway and so something still isn't right. It's responding to NS, so why isn't the NDP entry updating every minute whenever they are responded to?
There is something additional I've spotted with the NA from the ISP, the source IP is GUA but the target address is link-local. I don't mean destination ip, I do mean target address within the ICMPv6 payload - before the (rte, sol) below:
4 13:45:21.68 2a02:fb8::32 fe80::1c1e:54ff:fe8a:705 ICMPv6 82 Neighbor Advertisement fe80::4a5a:dff:fe5a:f2b7 (rtr, sol)
The NDP table is being updated with the target address, but it does not update the source ip into the NDP table. That might be correct behaviour, but if so then what is updating the source ip entry in the NDP table after 24 hours (for the situation it does).
I have also seen the situation with where the NDP entry was stale for 24 hours and strangely was updated, which kept it working and when using my previous tricks to get it to work. However, it was not consistent after every reboot and connectiviy was still unreliable.
I still beleive we are walking around some other root cause here, possibly two issues.
I do admit the spec is ambiguious and this is not prohibited within the spec, but this implementation is a good example of exactly not what the spec intended. However, it should still be working.
We should not be seeing the first hop GUA going stale for 24 hours anyway.