Filtering software: what it blocks, what it misses, and what to use

A web filter is a safety net, not a plan. This page explains what the net catches, which filter you already own without knowing it, and the point at which the effort belongs somewhere else.

Filtering software is usually the first thing a worried parent searches for, and the market is happy to oblige: subscriptions, dashboards, weekly reports. The honest version is shorter. Filtering is one layer, most families already own a perfectly good filter inside the devices they have, and the paid products earn their fee in a fairly narrow set of situations. This page walks through all three parts.

What a filter actually does

A web filter checks each address the browser asks for against categorised lists, and blocks the request when the address sits in a category you switched off. That is the whole mechanism. It works well against the established corners of the internet, because those are catalogued; it works poorly against a site created last week, because nothing has catalogued it yet.

The mechanism also defines the blind spot. A filter reads web addresses, so it has no opinion about what happens inside an app, inside a game lobby, or inside a private message. The situations that put children at real risk are conversations, and conversations do not pass through a web filter. Blocking websites solves the accidental exposure problem, which is real, and it is the smaller of the two problems.

The filter you already own

Every major platform ships a content filter free, attached to the parental-control system you may already have configured. Apple’s Screen Time can limit web content per child account, Google’s Family Link does the same for a supervised Android device and for Chrome, and Microsoft Family Safety filters Edge on Windows and Xbox. The step-by-step menu paths are in the iPhone, Android and Windows guides on this site.

The built-in filters share one important limit: each covers its own browser. Screen Time’s web filter governs Safari; a different browser installed on the same device may not be covered, which is why the app-approval setting matters as much as the filter. For a young child, one approved browser plus the platform filter is a complete answer, and it costs nothing.

One level up sits the router. Many home routers, and most internet providers, offer household-wide filtering that covers every device on the home network in a single setting. It is the lowest-effort option and it ends at the front door: a phone on mobile data has left the router behind.

What paid products add

Dedicated filtering products have existed for as long as families have been online. Net Nanny has been sold continuously since the mid-nineties and now leads with real-time content analysis; CyberPatrol, another name from the same era, is today part of the Net Nanny family. Products in this class filter across browsers, add per-app time schedules, and put every child device on one dashboard.

What the fee genuinely buys is convenience and cross-platform reach: one place to manage a household of mixed devices, instead of four platform menus. What it does not buy is a different mechanism. A paid filter is still a filter, with the same blind spot around apps and messages, and on phones the built-in controls sit deeper in the operating system than anything installed after the fact.

The purchase makes most sense for a household with several young children on mixed platforms, where one dashboard replaces real administrative work. It makes least sense as a response to a teenager, for reasons the next section covers.

Where filtering stops working

Three boundaries are worth knowing before you rely on the net. First, apps: the filter reads web traffic, so video, chat and game content inside apps passes it untouched, and app-level settings have to do that work. Second, novelty: a scam site registered this week is on no list, which is why the reading skills on judging a website matter alongside the software. Third, motivation: a determined teenager defeats a web filter with a new browser, a VPN or a friend’s hotspot, and the arms race that follows costs more trust than it protects.

None of this makes filtering pointless. It makes filtering a tool for the accidental and the young, and a poor tool for the deliberate and the older. The layer that covers what filters cannot is the set of house rules a family actually keeps.

What to run at which age

Up to about eight: one approved browser, the platform filter on, the app store behind a code, contact locked to known people. At this age the filter earns its keep daily, because everything it prevents is accidental.

Nine to twelve: keep the filter, and move the attention to age ratings, contact settings and spending. This is the age band where a paid dashboard can be worth the fee if the household runs several devices across platforms.

Thirteen and up: the filter becomes a courtesy net for genuinely unwanted content, kept with the teenager’s knowledge. The protective work has moved to agreements about time, money and what gets told at home, and no subscription substitutes for those.