How do web filters work?

Answer 1

Internet Filtering Software - Does It Really Work?In recent years as the internet has grownas a medium for entertainment, online pornography and related pornographic materials has exploded.

Understandably, parents are in a bit of a sticky dilemma. They want their children to reap the benefits all of the vast amounts of educational and experiential material found on the Internet, but on the other hand they know that they need to shield them from unsavory, undesirable and pornographic material

As a result, parents have turned to various types of parental control software.

one type of parental control software gaining popularity, is the so-called Internet filtering type of Parental control software.

Ideally, Internet filtering software works by attempting to block or filter out unacceptable content based on certain preprogramed parameters built-in to the filtering software.

Most Parental control filtering software focuses on web site filtering.

The goal is to prevent various web sites from being accessed by the user based on the type of content the site features.

Common filtering criteria might be pornography, hate sites, or a legal or violent content.

Internet filtering software can also be set by the parent to restrict or block individual web site addresses, as well as certain keywords or key phrases used in search engines.

But the reality is, that is a impossible task. with over one million plus new pornographic websites coming online daily, not to mention the pornography now found running rampant through social networking and bookmarking sites many software companies are finding it increasingly difficult to correctly filter out the sort of objectionable material.

One tactic taken by some parental control software companies is to have staff continually search for adult sites and other objectionable content in order to update their software's database to assure that your child is protected against the latest threats.

Some Internet filtering software even allows parents to submit questionable web sites that are not already contained in the database for possible inclusion.

Then the web site is reviewed and either added to the and sites list or they may allow it.

The overall problem to the "list of bad sites" approach is that these software program databases become so large, that Surfing the web while using this sort of Internet filtering software causes the web browser to run slowly as the software tries to filter and check against its internal database.

To get around this sort of web slowdown, many Internet filtering software companies tried to develop proprietary algorithms that use fuzzy logic to anticipate content that would be objectionable.

While these programs can be successful, even the best can only filter out at most about 80% of the pornographic material your child may stumble across.

And while a 80% success rate is pretty strong, it still leaves your child woefully unprotected and therefore defeats the purpose of the reason that will parents would buy an Internet filter in the first place.

Another common problem with Internet filtering software is that it is very common for its to block legitimate content accidentally.

Here's what we mean: let's say that your child was doing a report for school about Breast cancer awareness month.

Depending upon the threshold set for the Internet filter, it's very likely that the Internet filtering software would block the word breast. As a result, the child would not be able to go to legitimate medical content sites in order to gather information for a report.

Internet filtering software such as this is usually a good choice for parents wishing to protect the innocence of children 12 and under. However as children become older and more computer savvy, this type of software becomes less effective in many cases.

Parental control software companies like PC tattletale.com have recognized the traditional limitations found in content limiting and/or Internet filtering software and have taken a different approach to how filtering and content limiting are done.

Rather than trying to block every site or every instance of a pornographic or undesirable keyword, PC title to all caters to parents with more realistic expectations.

The PC tattletale program allows parents to enter in specific URLs or Web addresses that they want their child prohibited from visiting.

For example if a parent wanted to prevent their child from visiting my space.com, it would be a simple matter for the parent to type in the URL of my space.com into the PC tattletale program thereby restricting the child's access to that particular website.

Keyword blocking in PC tell tale works much the same way. The parent might enter into a list of words that they found objectionable and did not want their child to view.

Then, should the child try to go to a website that contained one of those locked keywords, the PC tattletale software would reread the page before loading it in the browser and then redirect the child to another webpage such as yahoo.com.

Answer 2

Two types of web filtering: "pass-by filtering" and "pass-through filtering".

"Pass-by filtering", like "WFilter Enterprise" or "Websense", enables you to monitor and filter internet access from a mirroring port in your switch.

"Pass-through filtering" needs to be deployed in a proxy server or gateway server.

More details can be found at the related link below.