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by avian 2536 days ago
> They removed NAT, which made laymen deployment difficult. I can’t just plug an IPv6 router behind another router (or 3-4 levels of routers) and expect it to just work.

Is this common, plugging consumer routers with NAT several layers deep? I haven’t seen that in the wild. The only time I myself tried it didn’t work for some unknown reason.

My only real gripe with IPv6 is the fact that Duplicate Address Detection seems broken on many Wi-Fi networks (clients for some reason see their own traffic as traffic from another node and trigger DAD, which shuts down IPv6 access). I’ve seen this on routers from multiple vendors and I believe it’s some bug in their broadcast/multicast implementations.

2 comments

Re consumers, I can’t comment on how common they are, but people will have the ISP router, and then their router. They should ideally bridge but that doesn’t always happen, either due to just not knowing you should do that, or the ISP router/modem is a piece of junk that doesn’t support bridging or has quirks.

In the commercial/business space it’s more common to see 3 deep. I see it every day. Petroleum in particular often has ISP Router -> Site Firewall/Router -> ServiceProvider Router, because the fuel tank monitoring equipment is behind its own router so the vendor can get remote access/send data back over VPNs they manage.

In retail environments, especially malls and concession stands within department stores, it’s common to be plugged into their network, which you’ll want your own firewall protecting your PCs etc. I’ve also seen businesses at the same office building pool resources and share the one internet connection, with each having their own firewall/router behind the primary site firewall/router.

There’s also hotspots, where the business both puts that infrastructure on a separate network from their back office, and the hotspots themselves are doing NAT too.

Also some payment processors these days are pushing for organisations to install their own router behind the customers network and route all payments via that (Rather than customer managed IPsec VPNs or straight TLS over the Internet).

Yeah it’s definitely common.

Mobile carrier NAT, mobile device hotspot NAT, vmware NAT - that's the most I've seen so far.

But IPv6 in home networks replaces the unreachability-because-of-NAT by unreachability-because-of-filtering. The usual home router protects your clients, and if it's not your box, you're out of luck.