I’ve been playing around with an ubuntu linux server connecting our two apartments together, and the aim of this port is to explain how i’m going about routing between two subnets, each with their own default internet router. I’m using the power of DHCP3 on my ubuntu box to set routing tables on all clients connecting to the network to properly route through the correct gateways.
The network topography looks like this:
Internet <--> [router a] <--> LAN 0 <--> [Linux Server] <-> LAN 1 <--> [router b] <--> Internet
So, hosts in LAN 0 must use router a to get to the internet, and hosts in LAN 1 must use router b to get to the internet, but hosts on both LANs must use the linux server to get to each other. Thus, the server must do IP forwarding / IP routing, and the clients needs the proper routing tables. To get around the dumbness of the DLink router a and b, i’m running DHCP3 on the server to hand out routing and IP information to clients on both networks.
The resources i’ve found useful in setting up this config is: