Strange routing configuration problem

[Sandeep kumar Davu]

I have 3 machines running freebsd 4.5. I want to configure one of as a router.
One machine (A) has a IP of 131.123.36.65 (dc0). This needs to be connected to 
another machine (B) 131.123.36.102 (ed1)through a machine (R) that has two 
network cards 131.123.36.98(dc0) and 131.123.36.101(dc1). The netmask for the 
every ip is 255.255.255.192  (CANT CHANGE THIS).


I am able to ping A to R, R to A. Firstly I could not ping B to R. I figured 
out that B was unable to find the lladdr or R and added a static route in R.

$route add 131.123.36.102 -interface dc1
$arp -s 131.123.36.102 _ll_addr_

Doing so I could ping from R to B.

Now heres the problem
>From B I can ping to one interface of R dc1. But I cannot get  to the other 
interface dc0 nor to A.

I have configured the machine R to be  a router. gateway_enable="YES"
router_enable ="YES"

Even this did not help at all. I dont know where I am doing a mistake.
There is something that needs to be filled in.
Can anyone please help me here.
I am stuck in this for days.

Regards
sandeep