1. Main router for connect to internet with ADSL connection.
2. seccond router for client in another room/floor.
I try to connect both router together with UTP cable CAT5e length 40m. so seccond router client can not to receive IP address form DHCP of main router but when I bring seccound router near main router it can do, then i want to know how long of cable can do when conect routers together?