Wednesday, March 16, 2011

How to Block Websites

This post explains different ways to block websites

In general, there are two ways to block websites:

  1. Block on the computer
  2. Block on the network before it reaches the computer.

Computer Based Website Blocking

As of 2011, most website-blocking tools  (including parental-control tools) are software that runs on the computer. For such software, there are a few types:

1. Block using browser itself, Microsoft IE allows blocking website with its setup, however this feature is very limited and adding a large number of URL list is difficult to impossible. Firefox with add-ons may potentially achieve site-blocking too.
2. Block using 3rd-party software, such as parental control software.
3. Modify the Microsoft DNS host file to block a list of websites by pointing them to a non-existing IP address.

Problems with software-based blocking: 
The problems of computer-based website-blocking is that it is very easily by-passed.
  -  Browser-based filtering can be defeated by using a different browser (note there are many free-download browsers).
  -  3rd-party software can be disabled or uninstalled. Even if it is hard to disable to uninstall, it can be easily defeated by running virtual machine on the computer or booting into a different OS (such as the user-friendly Ubuntu Linux). This will completely defeat the soft-ware based approach.
  -  Modifying the DNS Host file suffers the same problem as 3rd-party software.

Network-based Blocking

There are three categories of network-based blocking:
  1. DNS-based blocking. The most popular solution is OpenDNS.
  2. Router-based blocking.
  3. Network appliance such as eSafekids.

Problems with network-based blocking:

DNS-based blocking is easy to configure. However, it is also easy to by-pass. All the user needs to do is to change the DNS settings of the computer. Even if the computer is locked down, a virtual-machine or complete booting-into Linux with a new DNS will defeat it without evening leaving a trace. There are many freely available public DNS servers. Here is a list of them.

Router-based blocking is more difficult to bypass, however most, if not all, of them are very difficult to configure. It is relatively easy to block 10 or 20 websites, but to manually add all porn websites is not practical. Most routers only have a fairly primitive/simple web-blocking feature.

Where does eSafekids fit?

eSafekids combines the best of router-based blocking and the ease of use to make it an unique and ideal tool in blocking websites. It is on the network and therefore cannot be bypassed with software changes or installing a new Operating System on the computer. It downloads the URL blacklist from the server automatically so that user does not have to manually enter all the offending sites. Yet it also give user great flexibility to add more sites to block, or to overwrite with a allow-access decision. It is powerful yet very easy to use.

Read more on eSafekids at

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