Multiple NAT router

[Brian Candler]

On Fri, Jul 21, 2006 at 11:13:47AM -0600, Brett Glass wrote:
> I have an application in which I'd like a FreeBSD router to have 
> multiple, isolated LANS attached to it, each with the same address 
> space. The FreeBSD box would take the place of multiple NAT routers.
> 
> For example, I might want to have three internal Ethernet 
> interfaces on the FreeBSD box. Each would be connected to a LAN 
> whose internal addresses are 192.168.0.0/24. The FreeBSD box would 
> do NAT for all of them, and of course they could not "see" one another.

FreeBSD won't support this 'out of the box' - because of the problem that
you identified of having multiple NICs all with the same address range
assigned to them.

There's a project called 'vimage' which adds a separate virtual forwarding
table per jail. This might work for you, although all the natd's "outside"
interfaces would need to sit on the same interface, and I don't know if it
can do that.

Otherwise - you can run multiple instances of FreeBSD under a virtual
machine environment like Xen or VMware, and bridge all the 'outside'
interfaces together onto the same NIC.

Also - you may still end up with a separate outside IP per vimage or VM, so
maybe then you need another NAT instance to NAT all of those onto a single
IP address :-)

Regards,

Brian.