DHCPv6 "prepends" DNS on router
Model:CGA4131COM Vendor:Technicolor Hardware Revision:2.1 Serial Number:290123500 Processor Speed:1503 MHz DRAM Total Memory:1024 MB DRAM Used Memory:465 MB DRAM Available Memory:559 MB Flash Total Memory:512 MB Flash Used Memory:2 MB Flash Available Memory:22 MB
Trying to eliminate the "helpful" insertion of IPv6 DNS servers at the top of every host's resolv stack.
Even though I manually specify IPv6 DNS in the router configuration, it "prepends" the Comcast placeholder /advertising DNS (2001:558:feed::1 and ::2), which overrides all my internal DNS, disclosing internal lookups and devices to the Public Internet.
Is it possible to turn this "feature" off? I have internal DNSv6 running for static IPv6 (RFC 4193) configured LAN devices and would prefer to lookup local devices before forwarding to external systems to: preserve privacy (as much as practical), speed up resolution and control my own network as much as possible.
I have already disabled IPv4 DHCP (for the same reason) and using the router as my gateway /masquerade IP works fine, it's just the IPv6 side of things that is causing me grief at the moment. I have no objection to using the router's DHCPv6, as long as it honors my DNS servers first.
If it doesn't (or can't), then I need to figure out how to "turn off" DHCPv6 so that setting up IPv6 on my internal DHCP won't cause conflicts.
Searching other threads and looking at the guides published doesn't provide any guidance in this area, so I'm hoping someone here can help me with this conundrum.