Disable Internet but allow Intranet

[themanwiththeplan]

How can I disable users from going out onto the internet but allow them to use the intranet. I have 25 machines hooked up with patch cords going to a hub then going to a router. Any suggestions. I know internet filtering software will work, but is expensive i need it on all machines any other work arounds.

 

[manarth]

dirty hack 1: setup an invalid proxy on all 25 machines
dirty hack 2: remove the 'default gateway' setting on all 25 machines (which probably means setting static IPs)
dirty hack 3: unplug the router.

good luck!

<marc> i wonder what will happen if i press this...[ul][li]please tell us if our suggestion has helped[/li][li]need some help? faq581-3339[/li][/ul]

 

[themanwiththeplan]

What if I have dynamic IPS can this still work, and more importantly how can i change the proxy on machines?

 

[manarth]

this is a very simple trick which is easily overcome by anyone with a modicum of internet-savvy.

in IE:
- go to tools > internet options
- select the 'connections' tab
- click the 'lan settings' button
- tick the box marked 'Use a proxy server for your LAN...'
- enter an invalid address
- OK everything.

<marc> i wonder what will happen if i press this...[ul][li]please tell us if our suggestion has helped[/li][li]need some help? faq581-3339[/li][/ul]

 

[smah]

Many routers have a facility to block/restrict internet access by ip address or ip range. This would be the most correct thing to do but the 'dirty tricks' do work.

Another dirty trick you may be able to do with DHCP is to have the DHCP server give out bad/false/fake DNS server information or set your own DNS server and have the DHCP server give that out. That way people won't be able to surf to websites by domain name (they still could if they knew the site's IP address). But, be careful with this as it will also mess up any internal services that use DNS.