Last month Troy Hunt posted an interesting comment on his blog about the problems around the etiquette of allowing guests onto your home wifi network. In his post, Hunt notes that guests can be deeply offended at being refused access. This is understandable. If they are guests in your home then they are probably close friends or family. Refusing access can make it seem that you don’t trust them. However, as Hunt goes on to point out, it is not the guests per se you need to worry about. Anyone on your network can cause problems – usually completely unintentionally. In my case I have the particular problem that my kids assume that they can use the network when they are here. Worse, they assume that they may access the network through their (google infested) smart phones. Now try as I might, there is no way I can monitor or control the way my kids (or their partners) set up their phones. Nor should I want to.
Hunt asks how others handle this problem. Like him I don’t much trust the separation offered by “guest” networks on wifi routers. In my case I decided long ago to split my network in two. I have an outer network which connects directly to my ISP and a second, inner network, which connects through another router to my outer network. Both networks use NAT and each uses an address range drawn from RFC1918. Furthermore, the routers are from different manufacturers so, hopefully, any vulnerability in one /may/ not be present in the other. My inner network has all my domestic devices, including my NAS, music and video streaming systems, DNS server etc. attached. These devices are mostly hard wired through a switch to the inner router. I only use wifi where it is not possible to hard wire, or where it would make no sense to do so. For example, my Sonos speakers and the app controlling them on my android tablet must use wifi. However, there is no reason why my kids, who insist on using Facebook, need to have access to my internal systems. So I run a separate wifi network on the outer router and they only have access to that. The only systems on the external screened network is one of my VPN endpoints (useful for when I am out and about and want to appear to be accessing the wider world from my home), and my old slug based webcam. My policy stance on the inner network is to consider the screened outer network as almost as hostile as the wider internet. This has the further advantage that bloody google doesn’t get notification of my internal wifi settings through my kids leaving “backup and restore” active on their android phones.