Really need help..
How to block access to client who are using WIFI / Client ROUTER and doing sharing with other members. For this reason the operator is loosing ‘POTENTIAL’ customers.

How you can distinguish between five computers at one home and five computers at different homes sharing the same connection with nat?

You need to set ttl to 1 on the interface facing the clients.

Assuming the clients are connecting to wlan1 on your router.
This will stop non technically savvy clients from using a router and NAT to share your service. Clients must connect their computers/handheld device directly to your router.

Note: This technique can be easily defeated by a client with the right knowledge and a capable router.

Note: This technique can be easily defeated by a client with the right knowledge and a capable router.

I'd say that would be anyone that has heard of google these days...

Setting TTL looks elegant. And of course client can set his own TTL also...