VPN Issues with IPv6
I have recently received my new Firewalla Gold SE (amazing by the way!) and wanted to try out the WireGuard server. When using my cellular data with T-Mobile, I can connect and use the internet, however LAN traffic is non-existent. In my research, I found another post on these forums where another T-Mobile user found it is an issue with their network: they only assign IPv6 addresses, not IPv4. I confirmed this as the suspected issue by connecting to a different WiFi network and suddenly, I can communicate with my LAN. I tested OpenVPN as well and it has this same "issue." When I gave my friend (who uses a different carrier) a profile, he was able to communicate with my LAN. We used the Network Analyzer app (found on both Android and iOS by Jiri Techet) to confirm the IPs given to us by our carriers.
My question then is what if anything can I do in order to resolve this? I tried to increase the MTU from 1412 to 1452 (seen in the other forum post) to no avail. Using Termux and a random ping command someone suggested on StackOverflow, I find that I have an MTU of 1408 anyways, so increasing it won't help. I make a habit of not connecting to any other WiFi network than my own and family, so this would mean I cannot VPN in and talk to any of my home devices without connecting to an open, public WiFi and pray they don't block VPN traffic.
-
When I VPN into my Firewalla from my cell data, I am unable to communicate with my LAN devices. If I am connected to WiFi (on an external network, not meaning my own WiFi), then it is fine. The only difference I can find is that my cellular provider (T-Mobile) does not assign private IPv4 addresses, only IPv6.
-
Did you use the IPv6 address to VPN? If not, see this article https://help.firewalla.com/hc/en-us/articles/115004274633-Firewalla-VPN-Server and look at section with ipv6
-
I'm unsure of what extra setup is required for IPv6 to work. My WAN has always had IPv6 turned on with DHCPv6, the Wireguard server by default enables DDNS with "Dual Stack" selected. Even if I choose "Use IPv6 only" it does not affect anything. Is there a specific step you believe I'm missing? When it's using IPv4, it clearly shows an "IPv4 Address" listed in the DDNS menu. When I select IPv6 only, nothing happens.
-
The problem is with IPv6 only. My cell carrier (T-Mobile) only gives you an IPv6 address on their network. Anyone else I know with T-Mobile has this same issue with my Firewalla Wireguard VPN. If I connect to a network which provides me an IPv4 address, everything works fine.
I have tried DDNS, it does nothing in dual stack or IPv6 only. I've tried without DDNS, still no changes.
Please sign in to leave a comment.
Comments
16 comments