pl. tell me how to restrict inernet access in wire lan. There is 10 nos. system are connected with lan. For lan connection we are using D-link ethernet switch.
First you must control the router that is going to the internet and how easy it is depends on how advanced the router is.
If what you are asking for is a simple can access and can not access many routers have the ability to block by IP address.
If you want to block based on where they are going you are going to need a firewall. Some consumer routers can partially do this function using something called OPENDNS but a smart users can bypass this.
A real firewall tends to be too expensive for many people so they make their own using a extra PC and the free linux based firewalls but this is not a beginner project.
you can access the network switch/modem and block the systems by IP Address.
First you have to set the IP addresses of the systems you want to block.
then access the administrator menu of the router/modem. You can do it by typing in the address bar, the modem/router's IP address. D-link IP Address would be 192.168.1.1
from the left pane, choose MANAGEMENT - then ACCESS CONTROL - IP ADDRESSESS.