Does anyone have experience with using internal DNS server for IPv6? I've found that when using the default settings (prefix delegation enabled, SLAAC) there are some issues:

1. When settings a custom DNS server the prefix is changed (and hence the DNS server address is also changed)
2. When trying to use a private or link-local address it is not accepted by the router

It would be nice to have some way to provide IPv6 clients with a custom DNS server address, while retaining the recommended configuration with the ISP (not configuring static IPv6 address on the device).

Maybe there is some way to do this?