I'm new to OPNsense and may have missed something obvious, but I'm used to being able to configure multiple IPv6 prefixes on interfaces. The specific use case I have is:
* GUA PD obtained from WAN, advertised on LAN
* ULA advertised to LAN
At a minimum I'd expect an option to explicitly configure a ULA for an interface. They're useful for segregating routable traffic you don't want touching 2000::/3 like locally run proxies.
I tried specifying the prefix manually in the Router Advertisements for the LAN interface, but don't see it on the wire.
The only reference to configuring a ULA is in the context of NPT (which no one should ever use but if you wish to administer a broken network, all the best).
Were you ever able to resolve this? I've tried a few sets of steps I've seen, including setting a static ipv6 address within the /64 and still cannot routed.
edit: I solved this. I had to change the RA to Unmanaged.