I am hoping this is an easy question to write out, so if I am unclear on the scenario please let me know what other information I can provide to help with a solution.
I am working with a Cisco 2821 which I want to enable one of the Gig ports to allow an external routable IP to utilize. We currently have a firewall solution which the default route of the 2821 points to. We can currently use routable IPs on the firewall device, and we also have everything on the LAN side connecting to the firewall device (FD).
Currently, the 2821 uses both Gig ports to route seperate internal subnets to the FD, but I want to convert one to actually use a routable IP address. There is a 2 x T multilink and a 3 x T multilink (MPLS) ppp terminating to this 2821.
Given this setup, I have tried to assign a routable IP to the G0/1 port but I am unable to see it from the outside. I believe this is because the routable IP is using the default route of the FD instead of the next hop which would be the ISP's and not the internal hop of the FD. I can assign this same routable IP to the FD's interface and it works perfectly.
Can someone help me understand what I need to so with the route table and ACL's to allow what I need to happen? Thanks a bunch!