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Block Internet Access

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i have heard that a website or a set of web address can be blocked by configuring the DNS server as well as host file..

can anyone tell me how to block the access to internet, with the help of DNS server..

i have heard that we shud make a list of users and specify tat list into DNS server…

can anyone help me with this????

Topic

Clarifications

In reply to Block Internet Access

Clarifications

firewall

In reply to Block Internet Access

a firewall can block access. If you run linux you can use iptables.

thanks, but thats not wht i asked

In reply to firewall

hey thanks for ur post, but i think u have only read the heading and replied my topic…

i know that 3rd party software like proxy server and firewall rules can be defined and block the access to certain pages.

but i want to find out, instead of using the 3rd party software, are there any such rules which if defined in DNS server can block the access to ineternet…

Like right now, our network is such tat: our broad band cable is plugged directly into hub and the users and free to access any site.. but if the server system is off then none are able to connnect to internet…

so does any1 know more abt configuring the dns server such way to block the internet access…

please do share / reply…

misusing vocabulary a bit

In reply to Block Internet Access

It sounds like you’ve been told about blocking access to certain URLs using the domain name resolution parameters, specified in the hosts file. I’ve done this and it works by defining certain web pages as ‘hosted’ on your local loopback interface, 127.0.0.1

wow

In reply to misusing vocabulary a bit

can u plz brief me more on how to do thatt??

the file is called ‘host’.

In reply to wow

C:\WINDOWS\system32\drivers\etc\host

Look for the row beginning with ‘127.0.0.1’, and add the websites you want to block below the word ‘localhost’. It’s important to LEAVE ‘localhost’ there – this defines your own machine as the location of your own machine, essentially, and should not be changed. Just add other websites on subsequent lines, and whenever a browser is instructed to visit one of them, it will look for the page content on your internal ‘localhost’, ie your own computer, not on the Internet. It isn’t exactly a ‘firewall’ but it does allow you to block known-bad websites. A firewall is always a good idea, too, as it allows you to block bad traffic, even for sites that you don’t know to be bad yet.

HTH

Simple , yet effective!

In reply to the file is called ‘host’.

I like it! thanks.

Good if you have very few computers. Then you can configure it on each. Else (firewall server)

fine with small n/w but what if big network???

In reply to Simple , yet effective!

fine with a small network of lees then 10 comp’s nur if more then 10comps.. then its a headche…

can it be done with the help DNS server???

like blocking the users from access the certain domain, like for example to access:
orkut.com account –> u have to block the google.com\accounts…

so similar way, is ther any way to configure the dns server so tat i can block my users from accessing the orkut.com network…

Sure. Tell us about your network.

In reply to fine with small n/w but what if big network???

What type of hardware (& software, possibly)` are you using for DNS?

H/w n s/w

In reply to Sure. Tell us about your network.

H/w: Intel P4 2.4Ghz Dual Processor,
intel 845 GL Mother board,
1.25Gb RAM DDR,

S/w: Win 2003 Enterprise Edition
DNS, DHCP…

All the clients take the ip address’s from the dhcp server.

will u able to help me???

Start with something like this.

In reply to Sure. Tell us about your network.

http://www.examcram2.com/articles/article.asp?p=600983&rl=1

You should probably take & pass this test to be administrator of that system.

I found that using Google, by searching ‘windows 2003 server host file’.

This may also be useful:

http://www.microsoft.com/technet/security/prodtech/windowsserver2003/w2003hg/sgch00.mspx

[Author]

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