I’ve got a 493AH that I am setting up as a multi-gateway. There are 6 VLAN’s on eth1, subnetted out as /30’s with public IP addresses. On ports 3-8 there are DHCP servers set up to hand out private network addresses, with mangle rules to “mark routing” for each one, sending it out the proper VLAN and default route.
The problem I am running into is in trying to give a static public IP address to a customer. Is there a NAT or Mangle rule that needs to be in place to allow passthrough of the public IP and gateway? I have tried several different configurations, all to no avail.
Without owning the public subnet and having it routed to you so that you can have it available on your LAN, you are restricted to using NAT, or proxy-arp with an ugly hack.
First see if your ISP is willing to route you the public subnet so you can place it on your LAN. If that is not possible, check with your ISP and see if turning on proxy-arp on your router will cause them problems. If both answers to those questions are negative, then you are stuck with the NAT solution.