I've done it.
But still having problem.
say 192.168.4.25 ip address have max bandwidth limit 512 kbps/512 kbps. sometimes it works properly and sometimes it's not work, it goes to our max bandwidth say (1 mbps).
Do I block input chain?You can block requests to the particular address on the router, however it will not stop client from sending it.
The good idea would be to visit client or recommend to clean its PC from viruses (bad applications).