BLock a computer on the network

[pratjoehahn]

this is the flowchart of my network

Internet> cable modem > my computer> network switch> computers 1,2,3,4,5,6

so in my command prompt when i put in the command "ipconfig/all"

it showed this my host name - sever, primary dns suffix- ,node type - unknown,ip routing - enabled,WINS proxy enabled - no


so my computer behaves like a internet gateway for d other comps in my network

i wanna block a computer with ip 192.168.0.120 on my network from accessing the internet remotely from the main system.
help me

 

[eibgrad]

Depends on what you're using as your gateway software. ICS? I don't recall ICS having either IP or MAC filtering. You should probably be using a router, even a cheap one is better than using a PC and offers more of these types of features.

And beware, either is easily defeated by either configuring another IP address manually or by altering the MAC address. Amazingly easy for anyone w/ even a modest idea of how networking works and the ability to use Google search.

 

[pratjoehahn]

Depends on what you're using as your gateway software. ICS? I don't recall ICS having either IP or MAC filtering. You should probably be using a router, even a cheap one is better than using a PC and offers more of these types of features.

And beware, either is easily defeated by either configuring another IP address manually or by altering the MAC address. Amazingly easy for anyone w/ even a modest idea of how networking works and the ability to use Google search.

I DONT HAVE ANY GATEWAY SOFTWARE I JUST THINK MY COMP'S ACTING AS THE GATEWAY.

 

[eibgrad]

I DONT HAVE ANY GATEWAY SOFTWARE I JUST THINK MY COMP'S ACTING AS THE GATEWAY.

It can only act as a gateway if it's configured as a gateway using gateway software (e.g., ICS).

According to your diagram you have two network connections from that PC, one to the modem, the other to a switch leading to the other computers. Minimally those two networks would have to be bridged at the PC. But that's insufficient since without gateway software, each of those computers would be accessing the public IP space directly. Instead they need to be behind a specific type of gateway, one that supports NAT and DHCP. Depending on the gateway software used, it may include additional features such as IP and/or MAC filtering.

IOW, you or someone else had to have configured it specifically for this purpose.

 

[eibgrad]

Go to Start->Run, type "ncpa.cpl" (no quotes), and hit enter. Locate the network connection that leads to the modem, right click it, and select Properties. Under the Advanced tab, do you have ICS (Internet Connection Sharing) enabled?

 

[pratjoehahn]

Go to Start->Run, type "ncpa.cpl" (no quotes), and hit enter. Locate the network connection that leads to the modem, right click it, and select Properties. Under the Advanced tab, do you have ICS (Internet Connection Sharing) enabled?

oh that one yes one of my connections is shared


so how do i block a computer on my network

 

[Brian_tii]

I believe the recommendation was to purchase a real firewall that supports routing. Internet Connection Sharing isn't exactly the best way to accomplish what you're asking. As eibgrad stated, anyone that knows anything about this topic would recommend you purchase a dedicated firewall / router. It'll be eaiser, more configurable, and more secure... and it'll cost you less than $50 bux. Considering you don't need to leave your desktop running all the time anymore, you may just save that much money each year in electricity alone.

 

[eibgrad]

oh that one yes one of my connections is shared


so how do i block a computer on my network

Go to Start->Run, type "ncpa.cpl" (no quotes), and hit enter. Locate the network connection that leads to the internal network (where the PC you’re trying to block is located), right click it, and select Properties. Under the Advanced tab, you'll see a section called Windows Firewall (aka ICF) and a Settings button. If there was going to be any way to block outbound traffic from a specific IP address (or MAC address), it would be there. As far as I can tell (and what I always suspected), it's not possible using ICF. ICF is extremely simple and just meant to provide basic protection.

What you need to do is either replace ICS w/ an actual dedicated router (which will typically include a full-featured firewall), OR, install a replacement for the default ICF firewall on that PC. If you’re already using something like Norton Internet Security or similar anti-virus/anti-malware product, then it may already have a firewall of its own and you probably can use it to block IP and MAC addresses. If not, there are many other free firewall products to choose from (Comodo, Zone Alarm, PC Tools, etc.). It’s impossible to say which is best because the selection is so vast. But if you’re presently relying on ICF and what to try something, Comodo might be a good starting point.

http://www.comodo.com/home/internet-security/firewall.php

NOTE: Almost all these free products try to install additional items like toolbars, or change your homepage or default search, just uncheck those options.

 

[pratjoehahn]

Go to Start->Run, type "ncpa.cpl" (no quotes), and hit enter. Locate the network connection that leads to the internal network (where the PC you’re trying to block is located), right click it, and select Properties. Under the Advanced tab, you'll see a section called Windows Firewall (aka ICF) and a Settings button. If there was going to be any way to block outbound traffic from a specific IP address (or MAC address), it would be there. As far as I can tell (and what I always suspected), it's not possible using ICF. ICF is extremely simple and just meant to provide basic protection.

What you need to do is either replace ICS w/ an actual dedicated router (which will typically include a full-featured firewall), OR, install a replacement for the default ICF firewall on that PC. If you’re already using something like Norton Internet Security or similar anti-virus/anti-malware product, then it may already have a firewall of its own and you probably can use it to block IP and MAC addresses. If not, there are many other free firewall products to choose from (Comodo, Zone Alarm, PC Tools, etc.). It’s impossible to say which is best because the selection is so vast. But if you’re presently relying on ICF and what to try something, Comodo might be a good starting point.

http://www.comodo.com/home/internet-security/firewall.php

NOTE: Almost all these free products try to install additional items like toolbars, or change your homepage or default search, just uncheck those options.

OK i have kaspersky 2009 internet security on every one of my 7 computers..............any idea of blocking a computer using its firewall

 

[eibgrad]

If Kaspersky has its own firewall to replace ICF, then it should be possible. But since I don't use Kaspersky, I can’t provide specific instructions in configuring that particular firewall.

Most of these products have similar interfaces. There’s probably a firewall configuration option. In there it will offer to use some default firewall settings that can be overridden. Those overrides will usually include specific IPs, a range of IPs, MAC addresses, etc. Play with it a bit and see if you can figure it out. At least try!