hello all

i have made a server which is acting as a dhcp,dns and internet gateway in
scientific linux 4.5. Now i want my clients won't access some websites such
as orkut,facebook etc . Also i don't want to use proxy. Please help me .

thanks and regards

-- 
Vivek Chalotra
GRID Project Associate,
High Energy Physics Group,
Department of Physics & Electronics,
University of Jammu,
Jammu 180006,
INDIA.