Pro-tip: Notice I’m using the cloudflare DNS servers rather than the ISP-provided ones. The Comcast DNS servers have gone down on me before and their performance is generally lacking.
My concern was if the bridged router can’t contact IPv6 addresses, the same is probably true for the devices that are connecting through it.
I found the solution in this thread on the OpenWrt forums. While it’s easy to statically assign an IPv4 address, along with a default gateway and DNS server – for IPv6 it’s easiest to set up another lan interface specifically for IPv6 that gets it’s IPv6 address (and routes) automatically from the upstream router – rather than assigning it statically.
The TL;DR version of this post is to add this to your network config:
Configuring IPv6 Bridging through the Web Interface
To do the same thing above via LuCI – the OpenWrt web interface, here’s how. Initially on the Network -> Interfaces page, ou can see my IPv4 lan with the wan ports disabled:
Click “Add new interface…”
Name it “lan6” and choose the DHCPv6 client protocol. For the interface, select the @lan alias. Then click Create Interface. You’ll be brought to a second screen.
All I had to do on this page was change the “Request IPv6-prefix” value to disabled. No need to change anything on the other tabs – the defaults are fine.
Now the Status -> Overview page on my bridged router looks like this:
Now I can ping IPv6 addresses from the command line on my bridged router:
root@ap2:~# ping -c 2 ipv6.google.com
PING ipv6.google.com (2607:f8b0:4009:807::200e): 56 data bytes
64 bytes from 2607:f8b0:4009:807::200e: seq=0 ttl=115 time=17.884 ms
64 bytes from 2607:f8b0:4009:807::200e: seq=1 ttl=115 time=17.351 ms
--- ipv6.google.com ping statistics ---
2 packets transmitted, 2 packets received, 0% packet loss
round-trip min/avg/max = 17.351/17.617/17.884 ms
One of my 2021 goals is to better understand IPv6 concepts (at least as well as I can understand IPv4). If there’s any *nix configurations I find helpful along the way, I’ll post ’em here.
