Need to set "far gateway" to reach directly connected IPv6 router now?

[drosophila]

Since the previous update (noticed it after hotfix _8 but may have existed earlier), for IPv6 I need to set the gateway to "far gateway" to make OPNsense assign a default route for IPv6. This was not necessary before. I don't mind, but it still seems off somehow. The setup may be a little unusual in that (as some may recall from previous issues) my WAN interface has a bunch of different IP6 addresses, with two prefixes (one local and one public), because it is a router-behind-router setup but with the public side on the "interconnect LAN". Both addresses are assigned by the external router via SLAAC. To have reliable routing, reliable admin access and cohesive logs I set the route through the local address of the external router via the gateway configuration.
I assume that, once again, the ordering of the IP addresses matters, like with the gateway watcher. But the ordering is essentially random, so it must not be relied on, but since there is no "main address", the code cannot pin down which is supposed to be the "main" address. Also, I re-order the addresses via a script after the fact, but that should not normally affect the default route. The script removes and re-adds IP addresses, so it might be reasonable to assume that the default route gets purged when the respective address vanishes, but 1) there always is at least one address available in each prefix and 2) the issue persists across reboots, and it never failed before, and "far gateway" seems to reliably fix the problem.

So, long story short: is this intended? IOW, is it to be expected that the default route isn't set if the gateway has multiple prefixes, assigned by SLAAC?

[franco]

Far gateway is not enforced for IPv6 for historic reasons:

https://github.com/opnsense/core/blob/817f670cff30e4639bf362febdc6ed263514ea14/src/etc/inc/system.inc#L780

So something else must be going on.


Cheers,
Franco