Insert firewall in the middle of lan

[viktorasbumsteinas]

I have simple topology:
routerA(1.1.1.1 /30) connected to routerB(1.1.1.2/30)

I need to filter traffic between both routers (to allow only port 80 traffic from A to B).

I am not allowed to access routerA and routerB configuration.

But I'm allowed to put a router cisco 892(with two WAN interfaces and 8 LAN switch interfaces) in the middle.

Now I have topology:

routerA(1.1.1.1 /30) ----------892router----------routerB(1.1.1.2/30)

How can I configure router892 to accomplish the task?

[Bilal Nawaz]

Maybe you can do this: http://www.cisco.com/c/en/us/support/docs/lan-switching/integrated-routing-bridging-irb/17054-741-10.html

Ideally you'd want a transparent firewall, and not a router to do this task.