Please read this entirely...
I have a new lab area that is being setup in an existing building of a client of ours. The client already has an existing network that has VPN connectivity to our facility. We are being contracted to build this new lab and the techs that will be working in the new lab need connectivity to us also. But, we need to keep the 2 networks seperate. So, we are going to bring in one Cisco Cat 3500 XL series switch to connect to the new lab equipment and they will have a different ip address scheme than the existing network our client has, but this switch will also be physically connected to their network as well. So, we'll have one workstation that can see both networks (multihomed nic), another that's just on the new network, and one switch that needs to communicate on both networks to be able to give access to the existing old network to the multihomed workstation. Also, they currently have their entire "old" network NAT'd to one ip address for the VPN connection (which works because they are only accessing resources on our side right now), but how can I make the new network work through that existing VPN connection?
Hopefully this all makes sense, but please ask questions if you need clarification. Thanks for your help!