VPN/Firewall using virtual machine.

[dgiorgio]

I will use this framework in the Matrix and the Branches.

which VM have to use?
how do i interfaces "em0/em1" have internet connection?

VM will do VPN between branches.

modems are cable-modem.

NIC1 - em0 - (how to use?)
NIC2 - em1 - (how to use?)
NIC3 - OPT1 - bridged mode

[tester_02]

I would bridge them them all. 
What I do on the host vm for the adapter settings in windows on the adapter for your NIC1 and NIC2 is disable everything except the vmware bridging protocol.  That way only the vm gets and IP, and the host basically does not see the ones connected to the modems.

Your nic3 you leave alone as your host needs the internet connection also.