Linux as a router/firewall in network of virtual machines
I am looking for a solution to route traffic between VirtualBox virtual machines on different subnets of a virtual LAN.
It's my understanding that I could create/run a separate VM using a specialised router firmware distribution (eg OpenWrt, DD-WRT - see the Wikipedia list of wireless router firmware projects). For instance, I could follow the howto for running OpenWrt in VirtualBox on the OpenWrt wiki (tried posting the link but can't until I make 15 posts??).
As an alternative, is it possible to set up the virtual host with much of the same functionality found in one of these distributions - for instance, run Debian as the host machine's OS with router/firewall/DNS/DHCP functionality configured?
What might be some of the advantages/disadvantages of either approach?