How do I prevent internet access to a group of computers on my network?

3

Well I have the following setup...
Computer A , B and C are networked....
Computer A is connected to the internet, computer B and C are not setup for internet access currently but I guess its possible with some kind of setting they would eventually be able to access the internet and this is what I would like to prevent.
In summary only A should have internet access while A and B and C should still be on intranet.
Is this kind of config possible?, what kind of software or setup or tools would I need to achive this?

Kevin Boyd

Posted 2009-10-12T23:52:01.173

Reputation: 1 221

2From your comment, I'm not convinced a technological solution is best for your problem. – Captain Segfault – 2009-10-13T01:24:06.603

What else could be the alternative? – Kevin Boyd – 2009-10-13T11:28:44.923

Answers

3

Block their MAC addresses from accessing the internet in your router.

John T

Posted 2009-10-12T23:52:01.173

Reputation: 149 037

Currently I don't have a router but a switch.. can that also block mac addresses? – Kevin Boyd – 2009-10-12T23:55:41.447

Also what kind of tool can I use to find MAC address of the said computers does windows have anything like it? – Kevin Boyd – 2009-10-12T23:57:03.317

1If your switch has an administration page yes. The router/switch should show MAC addresses of connected nodes if they are active, if you want to obtain them manually run ipconfig (ifconfig on linux) or getmac from the command line (ipconfig would be easier to pinpoint the NIC card). If you explain your situation to us a bit better we can find a better solution. Are you simply trying to block kids from the internet? Take away the ethernet cable. – John T – 2009-10-13T00:05:55.857

Well my colleagues spend a lot of time on the internet rather than prioritizing their tasks, so I want to maintain network access with them but the internet access will only be to my computer... – Kevin Boyd – 2009-10-13T00:11:37.063

A router/switch that allows MAC filtering would be your best bet, if your current hardware cannot do it, you can buy a simple router without breaking the bank: http://www.newegg.com/Product/Product.aspx?Item=N82E16833127091

– John T – 2009-10-13T00:19:35.100

Is it possible that even if I block their mac addresses in the router they still could do some shared internet via my computer? – Kevin Boyd – 2009-10-13T00:22:27.627

1As long as your computer isn't configured as the gateway, then no. – John T – 2009-10-13T00:43:19.143

Note that it is relatively easy to spoof/change the MAC address. – Captain Segfault – 2009-10-13T01:21:36.047

2There are multiple ways to MAC filter, the method that should be chosen is "Only allow MACS in the allow list to access the internet" then he can simply add his, problem solved, you can do all the spoofing you want. And if your colleagues are that intent on getting on the internet rather than doing their work, I'd let higher management know. Going further than this shouldn't be necessary. Once you realized you've been blocked from something at work, trying to circumvent it is the last thing you should do if you value your job. – John T – 2009-10-13T01:31:49.387