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?

It is my understanding that DD-WRT and OpenWRT are for routes like Linksys. Why would you want to run a VM on these devices?

If you are looking to run VM's then instal a distro of your choice, I use Centos here, and create your VM's.

Run your interface in bridge mode and everything should be able to communicate with one another.

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Originally Posted by Lazydog

It is my understanding that DD-WRT and OpenWRT are for routes like Linksys. Why would you want to run a VM on these devices?

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That is my understanding too, but I came across a howto on the OpenWrt wiki about running OpenWrt in a VirtualBox VM, so it is apparently possible and there seems to be at least one other person interested in doing this kind of thing.

As I mentioned in my original post, I am not just looking to run VMs (I am doing that already), but am looking for a solution to route traffic between VirtualBox virtual machines on different subnets of a virtual LAN.

Given my limited knowledge of networking, it's my understanding that communication between different subnets needs to be routed - hence the post about either running a Linux-based router in a separate VM or configuring routing functionality on the virtual host.

Quote:

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Originally Posted by Lazydog

If you are looking to run VM's then instal a distro of your choice, I use Centos here, and create your VM's.

Run your interface in bridge mode and everything should be able to communicate with one another.

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I currently run Debian VMs in bridged mode. However the purpose of this post is to explore the possibility and/or the best way of isolating groups of VMs into subnets.

Have you looked at Configure Linux Virtual Local Area Network (VLAN)?