How do they do this ?

[archaicdude]

The following error pops up when I try to access some websites on my college computers.I can understand blocking certain torrent-related and *other* sites, but some like the following are blocked.
I just wanted to know how do they block/filter certain websites as they cannot sit and add every website to the block list.
eg- If I type "torrent", "thepiratebay", etc. the same error pops up with the typed url.
The following is a different example...
the site fifa.com opened but when I clicked on the photo link, the message appeared.
BTW, the images are allowed and displayed.

ERROR
The requested URL could not be retrieved

While trying to retrieve the URL: http://www.fifa.com/worldcup/photo/index.html

The following error was encountered:

* Access Denied.

Access control configuration prevents your request from being allowed at this time. Please contact your service provider if you feel this is incorrect.

Your cache administrator is root.
Generated Tue, 13 Jul 2010 09:28:51 GMT by proxy.*******.edu (squid/2.6.STABLE21)

[ibitato]

squid is a transparent proxy that will proxy all http connections no matter what (that is, there is no need of proxy config on your web browser, it will route/proxy the http traffic allways)
the transparent proxy (squid) has a black list of sites that can be configured by the admin

you can trace route all traffic, and check mayor activity and if desired, block the URLs

[archaicdude]

Originally Posted by ibitato

squid is a transparent proxy that will proxy all http connections no matter what (that is, there is no need of proxy config on your web browser, it will route/proxy the http traffic allways)
the transparent proxy (squid) has a black list of sites that can be configured by the admin

you can trace route all traffic, and check mayor activity and if desired, block the URLs

Thanks for the quick reply.
Ok, When I try to access a certain site...it is the server that proxies the connection but not the browser nor the present system ?
Is the black list of sites similar to those used in ad-blocking software, etc ?
That means, one should go thru a tedious process of adding sites/configuring the black lists ?
What I don't get it...why was the fifa one (and many other legitimate sites) blocked...is it also on one of its black lists ?

[ibitato]

Originally Posted by archaicdude

Thanks for the quick reply.
Ok, When I try to access a certain site...it is the server that proxies the connection but not the browser nor the present system ?
Is the black list of sites similar to those used in ad-blocking software, etc ?
That means, one should go thru a tedious process of adding sites/configuring the black lists ?
What I don't get it...why was the fifa one (and many other legitimate sites) blocked...is it also on one of its black lists ?

The transparent proxy will be filtering all your access and everyone else's
That doesn't mean that they do not have, also, software on each PC doing the same, like antivirus with parental control, etc .....

The process of filtering traffic and deciding wich pages to put down, it's fairly easy ...

Usually, you filter the http petitions by traffic and number of pettitions, and decide or not to black list them

also, there are public black lists over the internet, that you can just download and use in your proxy servers

The same goes for parental control and internet access control software, that might be installed in each PC; they can download the black lists and definitions from a central server seamless....

Also, many admin just black list sites in terms of TRAFFIC, they don't care if they are p0rn or not, they only want to keep excessive traffic down......

I understand taht fifa.com it's not a college must have web site, and giving the world cup, probably it's blocked due to excessive traffic hemmring the service and lowering people doign some seriuos stuff.....

[Finchwizard]

As someone who works in a school and manages Proxy servers and things.

I don't want Users spending excess times on doing nothing. As far as I'm concerned, Kids and Teachers are here to Learn and Teach, not sit on Facebook all day chatting with friends or playing games.

The proxy server is what is accessing the net, so they can block words in URL's, words within pages if we really want, or entire URL's or domains.

There's a lot of other options like weighted searches, so searching for Hardcore might get you +5 points, and Movies might get you another +3 points.

Which sometimes helps to not ban legit searches like movies, or even the word Hardcore when in relation to something else.