Lockdown Software?

[MrMistermister]

Hey guise,

 

So I'm the IT Specialist at my workplace (which is a call center), and I'd just like to know the best type of lockdown or whitelist/blacklist software we could install on our computers to keep people from using Facebook, Twitter, downloading stuff, etc. and only let a few websites through. Most computers run Windows 7, though some still run XP.

 

All computers are connected to the same network via Ethernet, so it doesn't matter if its network based or native. Preferable network based though, to keep me from installing new software on 30+ computers.

 

Thanks!

[MrMistermister]

I should probably also note, all computers are connected to a Linux server which could potentially (if not, already is) act as a proxy server.

[Electronics Wizardy]

If you can configure the router/proxy most buiness grade stuff like pfsense and untangle support a webfiler that can block most of these sites.