I'm planning to setup Zeroshell as a router gateway for a school network on Virtualbox.
The host machine will run Ubuntu server edition. Then I will install Zeroshell as a guest Os with 4 configured lan adapters each of which are mapped to the physical ethernet cards on the machine.
The physical machine is connected to 3 WANs each of which are connected to the Internet. For each WAN, i will configure each virtual adapter as either bridge or nat depending on where they are connected. Bridged mode for the 2 wans which are connected to a modem/router with PPPOE and NAT for the last wan which is a leased line runnning on a /29 network.
The 4th ethernet adapter is connected to the Internal Lan of the school. This will be configured as bridged mode. This will be used by the Zeroshell guest OS as the default gateway for its DHCP configuration. Note that DHCP server of the LAN is running on Zeroshell that is on a virtual machine.
My question is, will this setup work and will it scale? What kind of problems I might encounter in the future? What is the minimum hardware requirements that I must use to get a decent performance out of this setup?
I pity you and your predicament of having to build this kludge :)
There are no reasons why any of this wouldn't work. It will probably even scale quite well if you give the VM enough resources. I would still advocate against the use of Virtualbox in favor of KVM, as I haven't had many decent results with virtualbox and have had quite a bit of good results with kvm, both with and without virt-manager.
I would also still try to get rid of the virtualization layer by compiling drivers from source, but that's not everybody's cup of tea.