What it is
DNS blocking is a simple filter for where devices are allowed to go on the internet. When a user tries to visit a domain on the block list, the DNS resolver refuses or sends them nowhere - so risky or unwanted sites never load.
How it works
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Your device asks a DNS resolver for a site’s IP.
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The resolver checks policies/lists first.
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If the domain is blocked (malware, phishing, adult, gambling, etc.), the lookup is denied or redirected to a safe page.
Good uses
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Security: stop malware/phishing domains before connections happen.
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Productivity & policy: block gambling, pirated content, or shadow IT at work/school.
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Parenting: filter adult sites and risky downloads at home.
Limits & gotchas
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Not a silver bullet: won’t see encrypted IP-only traffic or block VPNs.
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Overblocking happens: legit sites can be mislabeled—allowlist when needed.
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Bypass risk: users can change DNS or use DoH/DoT unless you enforce it on the network.
Quick setup tips
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Choose a reputable DNS filter (supports categories, malware feeds, custom lists).
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Enforce at the router/firewall: force all DNS to your resolver; block outbound 53/853 to others.
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Turn on DoT/DoH to your chosen resolver to prevent tampering.
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Start in monitor mode for a week, review hits, then tighten.
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Maintain allow/deny lists and review alerts for false positives.