DNS Filtering or Web Filtering?

About this interactive

We type names, but packets need IP addresses, so the PC first asks a DNS server, often the firewall or router, what address belongs to the name. Regular web filtering lets that lookup succeed. The PC gets the site's real address and tries to connect, and the firewall or a proxy refuses the connection. Because it handles the traffic itself, it can see the full address, path included, and can check what comes back. DNS filtering acts one step earlier. When the name is banned, the DNS server answers with a different address, often a local machine that replies "access denied". The PC never learns the real address and never connects to the site. It is very easy to set up, but it sees only the name, so it blocks whole sites, not single pages, and it only works for machines that ask that resolver.

What you'll learn

Explain how DNS filtering blocks a site by answering the lookup with the address of a block page instead of the real one
Tell DNS filtering from regular web filtering at a firewall or proxy by what the defender sees: where the block happens and what each one can check

Aligned to

CompTIA Security+

4.5 Given a scenario, modify enterprise capabilities to enhance security.

Key terms

DNS Filtering: A security method that blocks access to malicious or unauthorized domains by intercepting and filtering DNS queries.
Web Filtering: A security mechanism that controls which websites users can access by blocking or allowing URLs based on defined policies.
Domain Name System: A hierarchical naming system that translates human-readable domain names into IP addresses.
IP Address: A numerical label assigned to each device connected to a network that uses the Internet Protocol.

Topics

Interactive Streak Sort

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