Simulate Direct Internet in Lab

I work for a Smart Home company, and we have been having issues with certain ISP routes killing updates. Therefore, we need to simulate an internet connection in our office for testing.

We have two networks, one of which we don’t use for testing as this is our main company network. We have another network connected to an ADSL line which is what we use for testing. This is behind a standard basic business router, and I need to then make routers within this network think they are internet connected without another router in the middle.

The kicker is because we need to evaluate mainly ISP routers, we cannot just set them on the LAN with static IPs and away we go. Preferably we’d simulate a VDSL/ADSL2 connection directly into the routers, but I don’t know how to do that.

Any help would be greatly appreciated, thanks

It’s possibly a better bet to simulate the effects. Things like broken MTU discovery, CGNATs and other various broken IPv6 and IPv4 networks, broken DHCP servers, middleboxes that rewrite TCP streams and rewrite TLS headers. You can simulate/test all of those with Linux containers.

MTUs are usually the biggest culprit, with VPNs getting popular