Simulating ISP IPv6 service

I need some help finding a way to simulate IPv6, as if from an ISP, so a connected router ‘sees’ all the expected IPV6 DHCP and such. My only available ISP just serves IPv4, so there is no way to test on an actual line; I need to simulate this.

Here is the background, I have a test rig that allows me to test IPv4 & VLAN support for a downstream router to validate my build and config to see if VLAN on the WAN and all that is working.
This has been great, I create a static interface, and it also serves up DHCP. I give it an IP from within my ISPs network to simulate a ‘public’ IP.
It looks like this:

config interface 'isp'
	option proto 'static'
	option ipaddr ''
	option netmask ''
	option ifname 'eth1.1000'

This has worked well for validating downstream router WAN VLAN support and such. But the question now is how to configure that interface to also simulate an ISPs IPv6.
Additionally, I’ll need a method to evaluate if the downstream config works, as we can’t run the usual websites that validate this. Or maybe the test router can run a 6in4 tunnel?

Any input is greatly appreciated.


IPv6 has been around for decades, you need to start shouting at your ISP to support it, or find another.

tunnelbroker requires your connection be a public, static IPv4. If you have that it works well. Another option is to set up a VPS with a company that has IPv6 then VPN the IPv6 connection back to your site. I don't know if any of the general consumer VPNs offer IPv6 on the VPN.

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Mullvad does support IPv6, I use it for WireGuard.
They also allow port forwarding via the VPN so that you can have a Public IPv4 address via your VPN

It needs to be public, but it doesn't need to be static. You can set it up to update a dynamic address as and when it changes.


Thanks for mentioning that, good to hear. I'm off to set up tunnelbroker and get that running for IPv6 on the 'Fake ISP' box.

Thanks to all for the feedback and ideas.

Next will be to figure out how to delegate a /60 to the cascaded router. Any tips welcome.

The lan needs to hold a /59 or larger. Then the downstream router should get a /64 in the first half of the /59 as it's wan IP, and the other /60 delegated to it.

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