Hello @Helmant,
Thank you for reaching out to our community for assistance with your modem/router setup. Congratulations on getting a jump ahead of the crowd. It is inevitable IPv6 is coming much faster than most people even know. I have included a link that will be very helpful to you. We do support IPv6. You would have to set your router to the passthrough option. We assign IP addresses by DHCP.
This is just a suggestion, by no way a sale's pitch, we have a subscription-based service called Cox Complete Care. They help with all of your networking devices and questions that are outside the scope of our support. They support the products that you own that are not Cox. The service also helps with virus removal, and service appointment fees(which is helpful when dealing with frustrating signal issues). It is only $10 a month with a 3-month subscription requirement.
If you have any other issues, please reach us on Twitter at @CoxHelp, visit us on Facebook, or email us at cox.help@cox.com. Provide us the name on the account with the complete service address with a link to this thread so we can get started.
Crystal S.
Cox Support Forum Moderator