Learn how to forward ports with firewalld for IPv4 and IPv6 destinations. 🕵🏻

After writing my last post on my IPv6 woes with my Pixel 3, some readers asked how I’m handling IPv6 on my router lately. I wrote about this previously when Spectrum was Time Warner Cable and I was using Mikrotik network devices. There is a good post from 2015 on the blog and it still works today: Time Warner Road Runner, Linux, and large IPv6 subnets I am still using that same setup today, but some readers found it difficult to find the post since Time Warner Cable has renamed to Spectrum.

On most IPv6-enabled networks, network addresses are distributed via stateless address autoconfiguration (SLAAC). That is a fancy way to say that hosts on an IPv6 network will configure their own IP addresses. The process usually works like this: The host sends out a router solicitation request: Hey, who is the router around here? The router replies with a prefix: I am the router and your IPv6 address should start with this prefix.

Although Time Warner Cable is now Spectrum and wide-dhcpv6 is quite old, this post is still what I’m using today (in 2019)! I’ve written about how to get larger IPv6 subnets from Time Warner Cable’s Road Runner service on a Mikrotik router before, but I’ve converted to using a Linux server as my router for my home. Getting the larger /56 IPv6 subnet is a little tricky and it’s not terribly well documented.

Time Warner has gradually rolled out IPv6 connectivity to their Road Runner customers over the past couple of years and it started appearing on my home network earlier this year. I had some issues getting the leases to renew properly after they expired (TWC’s default lease length appears to be seven days) and there were some routing problems that cropped up occasionally. However, over the past month, things seem to have settled down on TWC’s San Antonio network.