Either by law or simple innertia, you will be requested to setup a filtering box between your school’s network and the wild of the Internet. Appliances do a great job, and there are many options to chose from. You can also skip the up-front payment along with the “maintenance” contract these appliances come attached to by setting up your own “appliance”. I’ve used Squid, installed in a relatively cheap PC running some flavor of Linux. Right now we have a Ubuntu/Squid/Dansguardian setup going. For backup we use OpenDNS for filtering.
What we are able to accomplish with the Squid-box is filtering traffic to the Internet, block incoming connections and requests to internal addresses, keep an eye on our traffic in general and firewall out internal network from the external Internet.
When making decisions about equipment to purchase, bandwidth to contract or services to install inside your network, Squid traffic reports are a great tools to have on hand.
If you’re stuck and are not able to get Squid going for technical reasons, you can always fall back on the very reliable and free OpenDNS service. I cannot say enough about this service and how great it is to have. It requires very little maintenance, gives you a lot of flexibility and gets you going within a few minutes.