Matter over WiFi success story - enabled IP6 on Unifi network

I bought two Matter over WiFi devices from different vendors. When I tried to ad them, both started off okay using the Home Assistant app on my phone, but then timed out at “Checking network connectivity”. I had IP6 disabled everywhere on my network because I didn’t understand it, and IP4 was getting the job done. After I enabled IP6, I was able to successfully add the two devices to HA.

Matter doesn’t depend on the cloud; it can work using IP6 on your local network, even if your ISP doesn’t support IP6 for internet traffic yet.

In my network I have a separate vlan for IOT devices. Now I have IP6 enabled on the IOT vlan as follows:

I was unable to get Verizon to assign an IP6 address to my router, so I used a static Unique Local Address prefix. This is the equivalent of IP4’s, but the IP6 address space is so big that everyone can have their own globally unique private network.

I got a /48 unique local address from “fd97:776b:4246::/48”. The FD at the beginning marks it as a local address, and the rest are randomly generated.

We have a /48, and a full network prefix is /64, so I added “0001” to make a subnet.

I did the same on the default network, but with “0002”. (It might have been easier to remember if I had used the vlan numbers).

I left IP6 disabled on the Internet WAN interface, since Fios doesn’t support it in my area yet.

If your ISP supports IP6, they will delegate a prefix to you, and your router can hand that prefix off to devices.

IP6 is very different than IP4 -

  • Your ISP assigns you a whole address space, not just a single address you need to NAT.
  • Your devices will assign their own addresses. (Network prefix + MAC address?)
  • Every device will have one address for local link traffic, one for inside your entire network, and one for the Internet. And possibly more.

I liked this introduction to IP6, it really helped my wrap my head around it.

I hope folks will find my success story when they have a similar problem. I’m sure I got a bunch of stuff wrong, and any corrections you want to offer are welcome.