Application and Web Access Control over a network

Posted on 2007-04-01
Last Modified: 2010-05-18

I am looking for a product to offer me Application Control and Web Access Control over a network of 40-50 users.

I am currently running Windows Server 2003 SBS with MS Exchange.

I am also currently using Sophos Anti-virus and Client Firewall on all machines. Unfortunatelly the Sophos Firewall does not allow me to block certain apps or http access or certain ports.

Basically what I'm looking to block is MSN Messenger, Skype, Yahoo Messenger. Also block access to websites like, etc.

Any ideas?

Question by:cgru2
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Expert Comment

ID: 18834266
use hosts file to block
add following entry to your hosts files on all client machines
you'll find the hosts file here-
if you are using win 2000, windows directory will be replaced by winnt

is your firewall allows port blocking? if yes, you can block messengers using the port numbers they are using

Expert Comment

ID: 18846240
I would look at a router that will let be block all that stuff...   You could block URLs of websites, protocols (block msn always), and IP ranges/domains (of the protocol servers).  Go to D-Link and select a random router and look at it's emulator... you'll see all those types of filters available.  Similarly for Linksys and other companies.

You should already be able to do some of this with your existing router if you have one.  For instance a DI-604 is ancient (and cheapo) but it filters URLs, Protocols, and Domains easier/better than newers...
Your router may be similar.

Rather than modifying hosts individual hosts, I would just configure the addresses in the local dns server and create bogus domains. killing * and any number of other URLs network wide really simply.  You can even go in DNS and look at the DNS Cache to see what people are using to know out what to create -- (oh, lots of stuff there, no better to go to individual machine ipconfig /flushdns then start messenger or yahoo and use ipconfig /displaydns to see what domains they use).

AD group policies can be used to restrict some programs and ports on machines too by configuring the windows firewall and software policies.

Author Comment

ID: 18847718
Well I've got a CISCO 878 router for our internet access
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Author Comment

ID: 18847939
Phadke_hemant I've tested your solution on a workstation and it works fine. But the only issue is that I need to do that on each workstation. And everytime a new computer arrives in the offices, I will have to modify its hosts file.

Is there anyway I can do this via the domain controler, using ad or even a logon script to check or modify the hosts file entry?

LVL 10

Expert Comment

ID: 18848195
yes  you have to replace hosts file on all machines
you can use a logon script also
Do you have ISA server?? its a best way to block the contents on internet including programs/ websites/ messengers/ ports etc

Expert Comment

ID: 18850120
Like I said rather than modifying the hosts, you can just create entries in your AD's DNS server which all the machines should be using... as long as they don't use any other DNS servers it would be equivilant to putting it in the host files... in fact it's even better because you do have the option of using wild cards and block entire domains and subdomains....

Author Comment

ID: 18854491
OK that sounds like a good idea. So how do I go about actually doing this? I'm a newbie to AD

Author Comment

ID: 18854555
I went to Start-Administrative Tools-DNS

Then in the DNS tree i opened my domain controller then went to Forward Lookup zones and selected my domain.

There, is a list with all the computer names on my network of Type Host(A) and their IP address.

Accepted Solution

tymes earned 500 total points
ID: 18860626
No, start the DNS console.  Forward Zones, then start creating new zones (that are empty and not configured so they don't point to the corrent internet addresses).  Don't touch your own domain and you don't need to look at all your computers.

So a list of NEW zones to create to block messenger...

You may click on View Advanced and browse through all the names in the cache to find sites you want to block, look at Cached Lookups.(root) etc and and etc looking for suspects.

Or to learn what names an application uses, I go to a client machine, flush the dns:
ipconfig /flushdns
start the application and log in then type in:
ipconfig /displaydns |more
and it will list all the recent addresses.... scan the list for obvious ones...  using this method I was quick to find for msn messenger:
- (maybe not block this one as other things may use it).
now there may be different alias and other things using AD creating a new domain will block and all other subdomains...

So back to the list of zones to block... Start by creating new zones:

So for each of those create a New Zone, Make it a Primary Zone and store it in AD to all the DNS servers in your domain so they all start faking them too.

Author Comment

ID: 18886475
Thanks for that. Works great!

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