OpenWRT Wireguard IP problem with Community FIbre network

Installing and Using OpenWrt Network and Wireless Configuration
1

A while ago, I have set up a tunnel between Site A and Site B, using two openwrt routers with Wireguard that are connected to their respective ISP router. Having the same IP address for Site A to Site B is the aim of this configuration.

https://forum.openwrt.org/t/two-openwrt-routers-with-the-same-external-ip/154275/2

I am unable to use the same connection as I had with my prior ISP since switching to Community Fibre. When I checked the IP address on WhoisMyIP, I saw that it was different on the Community Fibre router. There is no connection even though I tried adding both IP addresses to the Site B Wireguard router. Which IP address should I use to set up Wireguard?

2

For wireguard to work, at least one if the sites must have a public IP address, is that your case?

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3

The addresses not matching means that something is doing NAT in between your OpenWrt router and the Internet. This will prevent incoming connections from working. Sometimes the NAT is in the modem/gateway box in your house and you can reconfigure it. If the ISP is NATing customers within their network (CGNAT) there is no way to have incoming IPv4 direct to your house with that service.

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4

The provider is definitely NATing the client network, (I'm 99% sure). What setting would be most appropriate in this case?

5

You can be sure, just by checking the IP address... Wireguard needs that at least one end has a public IP address. Some ISP put IPv4 behind NAT, but give public IPv6 addresses. Perhaps you can use an intermediate VPS. Or use other protocols, like zerotier.

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6

There was no handshake when I attempted to add the IPv6 address on the string below.

option endpoint_host '2a00:2345:dead:beef:1234:4567:89ab:cdef'

Is that how the IPv6 should be configured?

7

Do both devices have a public IPv6 address?

8

Yes. I believe so.

9

Try a test site to ping your IPv6 IP from outside. If the pings are answered, follow up by running tcpdump to confirm that your router is what is answering them.

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10

(Sorry for the late reply).
From Site A (home), I can ping6 the ipv6 router address 2a02:6b68:xyz:0000:0020 and the ipv6 from ifconfig.co 2a02:6b6f:xyz:f0f5:ca7c, but I cannot ping the ipv4 router.
From outside or Site B, I cannot ping any ipv6 and ipv4 address.

11

Any advise?