DNS filtering: blocking bad sites before they load

How it works

When you visit a website, your computer first asks a DNS server, the internet’s address book, where to find it. DNS filtering puts a check at that step. Before giving the address, the filtering service compares it with lists of sites known for malware, phishing and scams. If it matches, the connection is blocked.

Because nearly every connection starts with a DNS lookup, this catches threats from many directions: links in emails and texts, ads, malicious downloads trying to contact their operators, and mistyped addresses that lead to lookalike sites.

What it is good at

• Stopping known bad sites, including brand-new ones flagged by the service.
• Working everywhere, when installed on laptops, so it protects people at home and on public Wi-Fi as well as in the office.
• Blocking categories a business chooses, such as adult content or gambling.

What it does not replace

It judges the address alone and never sees what is on the page. A site that has not been flagged yet can get through, and so can a scam on a trusted platform. DNS filtering is one layer, alongside email security, protection on the computer and people who know what to look for.