Parenting 101

Martin Levins
10 December, 2007
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The protection of children on the internet has been a regular feature in many media for some time now and it’s been capped off recently with the Federal government offer of an internet filter for free (for three years) to every Australian family.

As educators, we are “in loco parentis” and have to look at the protection of our students in the same way as their real parents would. It’s tempting to think that banning some sites, will fulfil our responsibilities.

This is naïve, to say the least. Still, we always look for a magic bullet, one that will mean that we can click a button and we’re “safe” — but it’s a complicated business.

First, let’s ask what it is that we are trying to protect people against? This question may seem banal, but one man’s fish is another’s poisson — schools, parents and teachers will have differing expectations as to what is acceptable at what age and in what circumstances.

For example, the use of language that encourages the viewer to “make love elsewhere” will be considered inappropriate by many. We can resolve this by filtering the ABC web site because some vodcasts are liberal with the lip. But how can the computer discriminate between “The Chaser” (where language is rife), and “The Cook and the Chef” (where it isn’t — except when the gravy goes lumpy)?

So here comes some jargon, watch the step.

When a user sends a request for the computer interprets this as “make a TCP connection on port 80 to the machine at IP address” (a Domain Name Server somewhere will have already converted the human readable “” to the numerical address).

We could restrict the browser to contact specific, tested web sites only (a “whitelist”), which would be a fairly limiting experience, so let’s use a “blacklist” to block the offending address (or URL), using a URL filter. Good idea — until you realise that this can easily be bypassed. Requesting instead can foil the block on Therefore, we have to block both the name and its IP address.

However, if I use a third-party web site to fetch the inappropriate web site on my behalf (an anonymising proxy — see “Hotlinks”), then the filter doesn’t get to see the banned URL at all: it only sees the proxy.

Maybe it’s a better idea to ignore the address and look at the content of the page. “SafeEyes”, the latest Mac-compatible utility from the Feds’ NetAlert program, will do this — but it too can be foiled.
If my computer can connect using encryption, then the content cannot be analysed. If I convince my machine to use port 80 instead of the normal 443 for encryption, then I bypass any firewall blocks on encrypted channels. Again reasonably easy to do — there are recipes on the web!

“Parental Controls” — installed on the client as part of the operating system — are another example of a content filter. Leopard and Vista both have this functionality and, because the filter is part of the operating system, we would hope that it would work smoothly with any form of browsing. That being said, it’s already known that Firefox currently ignores the parental protection in Vista.

Whilst parental controls in Tiger were fairly rudimentary (essentially a whitelist), Leopard takes another road.

Leopard’s controls are content-based but, at the time of writing, it’s not clear how often they will be updated.

Unlike the Vista version of parental controls, Leopard’s controls work with any browser. Leopard can also control total hours browsing, use of iChat and Mail, can be remotely controlled from a “parent” computer or from Workgroup Manager, and parents or administrators can look for attempts to contact “banned” sites even if the History is disabled or cleared in the browser.

Filtration is fine, but there is no substitute for supervision, even if that just means noticing that the laptop lid gets closed very quickly on your approach. It’s criminal to do the Pontius Pilate thing — apply a filter and think that the problem is solved — or deny our kids access altogether because it’s too dangerous.

We don’t stop driving cars just because they haven’t got an airbag. We need to educate to overcome tabloid paranoia. Just like we teach kids to cross the road safely, we should teach them to negotiate the web safely

Knowledge is still the best filter and it’s free forever.

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