Protective DNS (often referred to as PDNS) is a DNS-layer security service that blocks or redirects DNS queries to malicious, suspicious, or policy-violating domains before a connection is ever made. It works as an early barrier against malware, phishing, ransomware, and command-and-control (C2) infrastructure.
PDNS is a functional category that describes a set of DNS-layer security capabilities rather than a specific product. However, various security providers offer PDNS-compliant services or solutions that deliver these capabilities like: blocking malicious domains, applying threat intelligence, and enforcing security policies via DNS resolution.
Governments have increasingly backed the use of PDNS. In 2021, the National Security Agency (NSA) and the Cybersecurity and Infrastructure Security Agency (CISA) issued joint guidance advocating for the adoption of protective DNS, recognizing its role in national and organizational cybersecurity resilience.
When a user initiates a DNS query, a protective DNS service inspects the request in real time, checking the domain against multiple data sources including:
If the domain is deemed safe, the query resolves normally. If it is identified as malicious or high risk, the service either blocks the resolution or redirects it to a safe page or sinkhole.
This process is typically passive, quick, and requires no end-user interaction, making it a zero-friction defense layer.
DNS is essential to the Internet’s function, and because it is so pervasive, it is frequently exploited by attackers. Threats like phishing, malware, and C2 communications often depend on DNS queries to locate malicious servers or transmit data.
Protective DNS is particularly valuable in:
PDNS reduces reliance on perimeter-based defenses like firewalls, which are less effective in decentralized environments.
Additionally, human error remains a persistent vulnerability. Even users with high security awareness may click malicious links or be tricked by well-crafted phishing attempts. Protective DNS provides a protective barrier before these threats can connect.
Protective DNS can be implemented via:
Deployment is typically quick and non-disruptive, making it scalable across devices and networks.
When selecting a PDNS service provider, organizations should look for offerings that align with NSA and CISA recommendations. These include features like:
|
DNS Layer |
Function |
Notes |
| Basic DNS |
Resolves domain names to IP addresses |
No built-in security |
| DNSSEC |
Authenticates DNS responses |
Ensures validity, not safety |
| DNS Filtering |
Blocks domains based on threat or content |
Often overlaps with PDNS |
| PDNS |
Applies threat intelligence at DNS level |
May include filtering, analytics, AI-driven detection |
| Encrypted DNS (DoH/DoT) |
Encrypts DNS queries in transit |
Enhances privacy, not filtering |
PDNS solutions often combine the benefits of DNS filtering, DNSSEC validation, and advanced threat analytics, delivering broader protection than any single DNS security layer.
Did you know? DNSFilter operates as both a PDNS provider and a DNS filtering solution, combining real-time AI-based domain classification with robust policy enforcement.
To see how organizations apply Protective DNS in practice, explore our Protective DNS use cases.
AI-powered DNS protection starts here. Try DNSFilter free and see how secure, intelligent DNS resolution keeps your network safe and fast.