How can I restrict users on the network from accessing web sites like facebook during business hours?

You can use your network router to block access to certain sitesIsaac Oben MCITP:EA, MCSE

Hello, Thank you for your post here. Yes, you will need a router/gateway such as Microsoft ISA server to restrict web access. In ISA server, you may create a Deny rule for specific URL (or IP addresses) and set the Schedule to enable the rule only during business hours. If you have any questions or concerns, please do not hesitate to let me know.