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I want to block all chat programs by blocking IP addresses


I want to prevent a group of users from using any chat program, whether it is through a web interface or through an .exe. I believe the easiest way would be to block the IP addresses of the chat programs. Since this is for a small number of users, I can do it on their local workstations (XP). I also can do it on the server although I would prefer to do it locally. I do not know how to block an IP address.

Thanks all,
1 Solution
I believe that you can accomplish this by manually editing each systems Host file.
This site gives some pretty good information on what a host file is, how to edit it, etc.
Bascially, once you enter the IP or URL that you decide to block that system will not be able to reach that web site.
Scott CSenior Systems EnginerCommented:
The only problem with blocking and IP address is that if the address of the chat server changes the users will be able start up again.

I think the best way to do this is to block the port that the chat uses.
erik77Author Commented:
I like that hosts idea because I want the simplest solution possible.

The problem with blocking ports is that the software will end up using port 80, not to mention some chat programs are web-based.

I think there is a problem with hosts because I want to block IP address, not web site names. I don't believe the host file can block ip addresses, only DNS names or am I mistaken?
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I think this URL clears up your last question.
Here's a small quote.
"But there's another common usage for the Hosts file: to block addresses. This is done by using a dummy address, typically, that goes nowhere. For example, consider this entry: wwww.yahoo.com
With this entry in the hosts file, any reference to www.yahoo.com will be redirected to the address Now that address is not a valid web address for any real web site. In fact, by convention it refers to your own computer.

I've been using this guy's HOSTS file (plus our additions) for about a year.
He updates it on a regular basic (1-3 times a month) and we keep our stuff updated in a Text file.
When he sends a new one, we just 'cut and paste' our stuff in and push it to our boxes.

Good Luck,

HOSTS file
You can use a HOSTS file to block ads, banners, 3rd party Cookies, 3rd party page counters, web bugs, and even most hijackers. This is accomplished by blocking the connection(s)) that supplies these little gems.

Win 98/ME = C:\WINDOWS

If you have a specific site or IP address you want to add or block, edit the hosts file as follows:
ADD:     companyweb  (enter the actual IP and company URL)
BLOCK:       badwebsite ( use the and the actual bad site)
You would normally do this through the router (DSL cable?) that is handling internet access. Find the port that the CHAT apps are using, and simply block that port.  Then if the chat apps try another port, then block that too on the router level, and keep going, until you block ALL ports that the CHAT apps use.
Cant you simply edit the firewall rules on your router to only allow specific subnets into your LAN?
A major problem that concerns web based messengers is that they connect to the messaging server server side, they do not set up a connection to the messaging server from the users system.
This means you will need to add all the IP's/addresses of any messaging server.
Another problem is that proxies can be used for messaging applications.

Are you looking to discourage casual use or to completely restrict the most determined efforts?
Greg GrothComputer Network SpecialistCommented:
Just add a few DNS entries to your Server.  Point them back to themselves with the  This will also work for web based chat sites.  You will need to change them once in a while but it shouldn't be that often.
Good Luck...
erik77  any progress?
The only true way to prevent chat rooms is to dis-able the internet access on teh chosen computers. Do this by installing a unique ip address to each user add  that to a firewall and block them.
s&d spybot can block ports.
SpywareBlaster doesn`t scan and clean for so-called spyware, but prevents it from being installed in the first place. It achieves this by disabling the CLSIDs of popular spyware ActiveX controls, and also prevents the installation of any of them via a webpage.

You might disable msn other common chat programs the .netpassport but there is another version of msn very popular these days E-buddy
Below we list a roundup of the Web's best and most popular free chat and instant messaging programs

 maybe this can help you
a whole page dedicated to different teckniques to blocking chat programs


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