Our network is accessing internet through a Speedtouch 512 ADSL Modem Router. The modem is connected to a Server which has another NIC connecting to our LAN via a Switch. And in that Server we have got Wingate Proxy for Internet sharing. LAN has network address of 192.168.0.0 where as Router has 10.0.0.0. So for wingate to work, the two NIC in the server is having ip address 192.168.0.1(connecting to LAN) and 10.0.0.3 (connecting to Router). Now for some reason we wanted one of the PC in Lan to access the router directly without going through the Wingate server so we just took a connection from router to the switch directly and we changed the ip address of that PC in the range of 10.0.0.0 . But if anyone changes the IP address of any PC to 10.0.0.0 range they can access the router. How can I configure the Router in such a way that it can only accept request from wingate server or that particular PC/ipaddress. That mean ony 10.0.0.3 and 10.0.0.1 should be able to access the internet.
Can anyone help me please