What Is Quad9 DNS? Protect Your Privacy

Every time you open a web browser, your device relies on an invisible directory system to translate human-friendly web addresses into machine-readable numerical locations. If this background system is sluggish or poorly protected, your personal data and devices remain constantly vulnerable to malicious intercepts and cyberattacks.

While most home networks default to the directory servers provided by internet service providers, these default setups rarely prioritize security or privacy. This is why many users switch to dedicated third-party resolvers.

Quad9 is a Swiss-based public resolver designed to automatically block malicious connections while protecting user privacy.

Definition and Core Functions

The internet relies on a decentralized directory system to connect users with websites and services. Gaining insight into how these network connections are established is essential to managing modern security and privacy.

DNS Concepts and the Role of a Resolver

Every online action starts with a Domain Name System lookup. Computers communicate using numerical Internet Protocol (IP) addresses, such as 192.0.2.1, while humans prefer names like example.com.

A recursive DNS resolver acts as an intermediary. When a user requests a website, the local device sends a query to the resolver.

The resolver then queries a hierarchy of root servers, top-level domain servers, and authoritative servers to retrieve the correct IP address. Once obtained, this address is returned to the user’s device, allowing the browser to load the site.

The Origin and Mission of Quad9

Quad9 was established in 2016 as a collaborative project between the Global Cyber Alliance, Packet Clearing House, and IBM Security. It began with the goal of creating a secure DNS resolver that is completely free to the public.

To ensure long-term independence and prioritize user privacy, the organization reorganized as a public-benefit, not-for-profit foundation and relocated its headquarters to Zurich, Switzerland. The primary mission of Quad9 is to provide robust, enterprise-grade cybersecurity protections directly to everyday internet users, bypassing commercial motives and data monetization.

Primary IP Addresses and Configuration Options

Quad9 provides multiple configuration endpoints depending on individual security and performance preferences. The standard secure service is hosted on the memorable IPv4 address 9.9.9.9 (with 149.112.112.112 as the secondary) and IPv6 address 2620:fe::fe.

This default configuration automatically filters out known malicious domains, validates queries using DNS Security Extensions, and does not send EDNS Client Subnet (ECS) data, preserving user anonymity.

For users who require specific network behaviors, Quad9 offers alternative configurations. The secured service with EDNS Client Subnet (ECS) support uses 9.9.9.11 (with 149.112.112.11 as the secondary).

This option sends a portion of the user’s IP address to content delivery networks to optimize localized performance, though at a slight cost to privacy. Alternatively, the unsecured service at 9.9.9.10 performs basic DNS translation without any threat filtering or security validation, which is useful primarily for troubleshooting network anomalies.

Security Mechanisms and Threat Intelligence

Public DNS resolvers generally translate addresses without analyzing the destination. Quad9 differs by integrating active threat intelligence directly into this translation phase to prevent connections to harmful servers.

Domain Blocklists and Collaborative Partners

To identify and block dangerous domains, Quad9 aggregates threat data from dozens of independent security intelligence partners. This includes data from specialized security firms, public sector agencies, and research groups.

Rather than relying on a single list, the system cross-references these feeds. A consensus-based methodology determines which domains to block, ensuring that high-threat destinations are neutralized quickly while minimizing the chances of blocking legitimate websites.

Protection Against Malware and Domain Fraud

By stopping threats during the resolution phase, Quad9 prevents devices from contacting malware, spyware, and phishing sites. If a device attempts to connect to a known command-and-control server used by a botnet, the query is blocked, and the threat is contained before any data can be compromised.

This approach is highly effective for protecting smart home devices and Internet of Things hardware. These connected devices typically cannot run traditional antivirus software, making network-level DNS filtering an important layer of security.

DNS Security Extensions and Protocol Encryption

Secure routing also requires verifying that the IP addresses returned have not been altered. Quad9 fully supports DNS Security Extensions (DNSSEC), which uses cryptographic signatures to authenticate that the DNS data received is genuine, preventing cache poisoning and redirect attacks.

To protect against local eavesdropping, Quad9 supports encrypted transport protocols. Users can route their queries using DNS-over-TLS (DoT) or DNS-over-HTTPS (DoH), which encrypts the connection between the user’s device and the resolver.

Privacy Framework and Legal Protections

While web security is a major focus, data privacy remains equally important. Quad9 maintains a strict legal and operational framework to protect the identity and activities of its users.

Zero-Log Policy on Personal Information

The foundation operates under a strict zero-log policy. Unlike commercial providers that track user habits, Quad9 does not collect, store, or monetize the IP addresses of its users.

The servers do not log any personally identifiable information. Only anonymized, aggregated telemetry data is processed.

This includes basic information such as the volume of queries and general geographic patterns, which is used strictly for capacity planning and generating public threat reports.

Swiss Jurisdiction and Data Protection Laws

In 2021, Quad9 moved its legal headquarters from California to Zurich, Switzerland. This transition placed the foundation entirely under Swiss jurisdiction, which features strong privacy laws.

Under this legal framework, global users are protected by Swiss data protection regulations. The organization cannot be compelled by arbitrary foreign search warrants or mass surveillance programs to collect or share user data, providing a robust legal shield for personal web traffic.

Global Anycast Architecture and Privacy Compliance

To deliver low latency, Quad9 uses a global anycast architecture. This means identical IP addresses are announced from over two hundred server clusters worldwide, and queries are automatically routed to the nearest available server.

This physical distribution is designed to comply with local privacy standards. For instance, European queries are handled by servers located within Europe, ensuring compliance with the General Data Protection Regulation (GDPR) and similar regional frameworks.

Comparison with Alternative DNS Providers

Choosing a third-party resolver involves balancing speed, security features, and privacy policies. Comparing Quad9 with other major public options highlights where it is most beneficial.

Performance and Latency Metrics

Although security filtering introduces brief processing times, Quad9 maintains high-speed performance through its distributed anycast network. In many regions, the response times are comparable to or faster than those of standard ISP servers.

While some commercial non-filtering services might have a minor advantage in raw speed, the difference is often unnoticeable in everyday browsing, making the security trade-off highly favorable.

Contrast with Google Public DNS and Cloudflare

Google Public DNS and Cloudflare are two of the most widely used alternative services. Google DNS is fast and reliable but is operated by an advertising corporation that retains user logs for temporary diagnostic periods.

Cloudflare provides exceptional speed and security filters, but operates as a for-profit commercial entity. Quad9 differs significantly by operating as a non-profit public-benefit foundation, ensuring that its primary motivation remains user security and absolute privacy rather than corporate growth or commercial telemetry.

Customization Limitations versus Specialized Providers

Some users prefer full control over their network filtering. Providers like NextDNS or local options like Pi-hole allow users to build custom blocklists, filter specific ad categories, or set parental controls.

Quad9 does not offer this level of customization. It functions entirely on an automated blocklist model designed to filter out malicious content while leaving legitimate traffic untouched.

For users seeking a simple set-and-forget security tool without administrative overhead, this automated approach is highly effective.

Deployment and Setup Instructions

Configuring your devices to use Quad9 is a straightforward process that does not require installing specialized software. It can be applied to individual systems or implemented network-wide at the router level.

Device-Level Configuration

Setting up the resolver on a personal computer or mobile device ensures that the security protections remain active even when connecting to external networks.

For Windows:

1. Open the Start menu, type Settings, and open the app.
2. Go to Network & Internet, then click on Advanced network settings or Change adapter options.
3. Right-click your active internet connection and select Properties.
4. Select Internet Protocol Version 4 (TCP/IPv4) and click Properties.
5. Choose Use the following DNS server addresses, then enter 9.9.9.9 as the Preferred DNS server and 149.112.112.112 as the Alternate DNS server.
6. Click OK to save the changes.

For macOS:

1. Open System Settings and click on Network in the sidebar.
2. Select your active Wi-Fi or Ethernet connection and click Details.
3. Click on the DNS tab in the left-hand menu.
4. Click the plus icon under the DNS Servers list and type 9.9.9.9.
5. Click the plus icon again and add 149.112.112.112.
6. Click OK and Apply to complete the setup.

For mobile devices (iOS and Android):

1. On iOS, go to Settings, select Wi-Fi, tap the information icon next to your network, select Configure DNS, choose Manual, and add the Quad9 IP addresses.
2. On Android 9 or newer, you can set a private DNS provider by going to Settings, Network & Internet, Private DNS, selecting Private DNS provider hostname, and typing dns.quad9.net.

Network-Level Setup on Routers

Applying the configuration directly to a home router protects every connected system without needing individual setup.

1. Open a web browser and type your router’s IP address (typically 192.168.1.1 or 192.168.0.1) to access the admin panel.
2. Log in using your router’s administrative credentials.
3. Locate the WAN or Internet settings page, which usually contains DNS settings.
4. Change the primary and secondary DNS server fields from Automatic or ISP-assigned to 9.9.9.9 and 149.112.112.112.
5. Save the settings and reboot your router.

Once applied, all smart home appliances, IoT devices, and guest networks automatically route through the secure resolver.

Verification of Active Protection

After updating the configurations, you can easily verify that the setup is working correctly.

1. Open a web browser and visit a diagnostic website such as dnscheck.tools or the official test domain provided by Quad9.
2. Confirm that the listed DNS resolver belongs to Quad9.

Conclusion

Using a secure, non-profit public DNS resolver offers an immediate defense against automated online threats. By substituting default ISP configurations with Quad9, you obtain security filtering and strong Swiss privacy protections at no cost.

This simple, one-time configuration change ensures that your devices remain protected against malicious activities while keeping your personal web traffic private.

Frequently Asked Questions