Kids outsmart Web filters

By Stefanie Olsen
Staff Writer, CNET
Published: April 19, 2006 4:00 AM PST

Last November, Ryan, a high-school sophomore, figured out a way to outsmart the Web filters on a school PC in order to visit the off-limits while doing "homework" in the computer lab.

A teacher eventually spotted the social network on the screen in front of "Ryan," a fictitious name for a real student attending school in Phoenix, Ore., a small town with a population of about 5,000. The teacher flagged the activity for the school's technology expert, who then followed Ryan's tracks online through the school network.

Ryan had apparently set up a so-called Web proxy from his home computer so that when he was at school, he could direct requests for banned sites like MySpace through a Web address at home, thereby tricking the school's filter. (Web, or CGI, proxies can be Web sites or applications that allow users to access other sites through them.)

"I eventually tracked down the (Internet Protocol) address, so that it doesn't work for him anymore," said Don Wolff, tech coordinator in the Phoenix-Talent School District, adding that Ryan didn't face disciplinary action. "It's against our acceptable-use policy, but he's not going to quit trying, (and this way) we can keep learning."

"This is a hot new trend among kids for getting around Web filters," Wolff said.

"It's going to be the constant battle. No matter what you put up, kids are going to work around it."

-- Lynn Beebe, school counselor

Web proxies are almost as old as the Internet itself as a means to route Web traffic through an anonymous domain name or circumvent content-filters, and they've long been the territory of corporate networks and the tech savvy seeking privacy. Nowadays, an increasing number of teenagers are setting up proxies on home PCs to sidestep school filtering traps, in addition to using free proxies set up on the Web, according to technologists at schools and at content-filtering technology providers.

Proxies are just one of many tricks that kids use to break locks put on forbidden material--a pursuit of almost any young generation. As more schools place tight controls on PCs to stop kids from file-sharing, instant messaging, social networking or looking at undesirable material online, the kids are getting more clever, tech experts say.

Google, by far the most popular search site, has a "safe search" feature, for example, that filters out adult material. But kids can circumvent those filters by viewing "cached" links or thumbnail images to look at inappropriate material, experts say. Teens also trick filters by typing in misspelled words or modern slang to retrieve links to racy material. Translation sites Babelfish or Google Translate can deliver sites like translated from another language.

"It's going to be the constant battle. No matter what you put up, kids are going to work around it," said Lynn Beebe, a school counselor in Scotts Valley, Calif. Her school, for example, uses filters to block all sites with the word or subject "blog," in addition to other sites.

But there's no foolproof solution. Beebe said that a small population of boys at the school use their free time to play games online. Sometimes they've shared with her that when they mistakenly type in a URL, an undesirable site appears, she said.

A more popular avenue for teens on school PCs is to visit any one of thousands of Web proxy sites such as Proxify, and to call up banned sites without notice, according to filtering companies.

Kevin Sanders, senior software engineer at Lightspeed Systems, maker of a content-filtering system called Total Traffic Control, said he targets such proxy sites in a master database of thousands of barred sites for school clients.

Proxies can get trickier.

"A far more difficult problem to deal with is when they download a piece of software on their home computer, using a CGI script to (access content). Our product doesn't recognize it as a known domain, because it's just going through their home computer," said Sanders.

Web sites like Freeproxy point visitors to many free downloadable applications like "" that let kids work around content filters in a more surreptitious way. Teen blogs can also be found that point kids to proxies for school filters.

How to deal with it? "We block all requests going to unknown sites," Sanders said. Lightspeed keeps a database of roughly 2 million recognized sites categorized in groups like News, Adult or Violence. School clients or administrators of the product can limit access so kids can access only acceptable categories such as News or Education. For Sanders, if a site goes unrecognized, he simply bans it.

"We also have a new feature coming out very soon which will allow us to dynamically detect the use of CGI-based proxies and block that session and send a notification to the network administrator," said Sanders.

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