Hello,
In my small office, we have DSL with 13 assigned IP addresses. Currently, two Cisco ASAs and some other devices connect to our DSL modem through a switch, and so each responds to ARP requests from the DSL provider for the public IP addresse(s) assigned to each device.
I would like to place a router in front of these devices, to better support routing to my secondary ISP (cable), using PBR.
I don't want to add yet another layer of NAT to my network, so I asked my ISP about giving me a separate public IP address subnet (30 bit mask); I would then assign one of those addresses to my router's outside interface, and then the ISP would update their routing tables to show that address as the gateway to my currently assigned public IP addresses. Sort of like a typical serial-link WAN connection. They won't do it, unless we sign up for enterprise class circuits, which is out of budget.
So, I was thinking, is there a way I can configure my Cisco 1921 router so that the DSL-facing interface responds to ARP requests for my entire range of 13 IP addresses, and then routes out another interface to the LAN where the host that actually has that IP address is, without translation?
I figure proxy ARP will do it, but I wonder if anyone who has done this can share configuration tips, since I will have to put an IP address in the same subnet on the outside and inside interfaces.
