And that, my friends, is where backend validation comes into play. We don't care about that setting (it will be overwritten once it gets online anyway), but we need to be able to enable DNS override and set a local IPv6 DNS server. That, however, will block the page from saving any other changes. The subnet checking algorithm they have, however, is broken (or the arguments to it - I don't recall it properly). This is because the first field in this page, the IP address, is writeable and is filled with the IP address we got from the ISP. That would, normally, be very easy - just open the web UI, LAN setup and change the DNS servers on IPv6:Įxcept there's a bug in this interface: any change you try to make, it will reply you with an error: IP address must be in the subnet of ::/64. But feel free to read the rest, as it's pretty interesting what you can get. I needed to change that! Ricardo from the future here: if you're here to just change the IPv6 DNS on your modem and need a simple route, you can go straight there - it's at the bottom of this post. However, the IPv6 range is given by my modem through Router Advertisements packets, and it sends itself as DNS server, essentially making all IPv6-enabled devices bypass the damn blocker. we surely can play with it, right?īackground story: I have a Pi-hole running at home and it listens to both IPv4 and IPv6. Fancy thing, but for obvious reasons I cannot disassemble it. I switched from my trusty DSL to a cable ISP a while ago and decided to take a deeper look at their modem - an Arris TG1692A.

How to hack into arris cable modem