Quad9 Explained: How This Free DNS Service Protects You

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Quad9 Explained: How This Free DNS Service Protects You

The internet is an indispensable part of modern life, a vast digital landscape we navigate daily for work, communication, entertainment, and information. Yet, beneath the surface of seamless browsing lies a complex infrastructure, and like any vast territory, it harbors hidden dangers. Malicious websites, phishing scams, spyware, and botnets lurk in the digital shadows, posing significant threats to our security and privacy. While firewalls and antivirus software are essential layers of defense, there’s another crucial, often overlooked, component that can significantly bolster your online safety: the Domain Name System (DNS) resolver you use.

Enter Quad9. Launched in 2017, Quad9 is a free, public, and recursive DNS service with a distinct mission: to protect users from malicious internet domains, enhancing both security and privacy without compromising performance. It operates as a non-profit organization, driven by a commitment to improving the internet ecosystem for everyone.

But what exactly is DNS, and how can changing your DNS provider, specifically to Quad9, make such a difference? Why choose Quad9 over the default provided by your Internet Service Provider (ISP) or other well-known alternatives like Google Public DNS or Cloudflare DNS? This comprehensive article will delve deep into the world of Quad9, explaining its underlying technology, the specific threats it mitigates, its robust privacy stance, performance characteristics, and how you can easily implement it across your devices. Prepare to understand how a simple change in your network settings can provide a powerful layer of automated protection against a wide array of online threats.

I. Demystifying DNS: The Internet’s Phonebook

Before we can appreciate Quad9’s role, we must first understand the fundamental technology it leverages: the Domain Name System (DNS). Think of DNS as the internet’s global phonebook or address directory.

Humans interact with the internet using memorable domain names like www.example.com. However, computers and network equipment communicate using numerical Internet Protocol (IP) addresses, such as 93.184.216.34 (for IPv4) or 2606:2800:220:1:248:1893:25c8:1946 (for IPv6). When you type a website address into your browser, your device doesn’t inherently know the IP address associated with that domain name. It needs to look it up. This lookup process is the core function of DNS.

The DNS Resolution Process (Simplified):

  1. User Request: You type www.example.com into your browser and hit Enter.
  2. Query to Resolver: Your computer or device sends a DNS query to its configured DNS resolver (often called a recursive resolver). By default, this is usually a server operated by your ISP.
  3. Resolver’s Job: The recursive resolver’s task is to find the correct IP address for www.example.com. If it has recently looked up this domain and has the answer cached (stored temporarily), it can respond immediately.
  4. Querying Authoritative Servers: If the answer isn’t cached, the recursive resolver initiates a series of queries:
    • It first asks a Root Server: “Where can I find information about .com domains?” The Root Server points it towards the Top-Level Domain (TLD) servers for .com.
    • It then asks the .com TLD Server: “Where can I find information about example.com?” The TLD Server points it towards the authoritative nameservers specifically responsible for the example.com domain.
    • Finally, it asks the Authoritative Nameserver for example.com: “What is the IP address for www.example.com?”
  5. Response to Resolver: The authoritative nameserver provides the IP address (e.g., 93.184.216.34) back to the recursive resolver.
  6. Response to User: The recursive resolver sends this IP address back to your computer.
  7. Connection: Your browser now knows the IP address and can establish a direct connection with the web server hosting www.example.com to load the webpage.

This entire process happens incredibly fast, usually in milliseconds, making web browsing feel instantaneous. However, the choice of which recursive resolver (Step 2) handles your queries has significant implications for your security, privacy, and even browsing speed.

II. Enter Quad9: A Guardian at the Digital Gates

Quad9 (represented by the easy-to-remember IP address 9.9.9.9) is a public recursive DNS resolver, but with a crucial difference from standard resolvers: it incorporates a layer of security intelligence.

What is Quad9?

Launched on November 16, 2017, Quad9 is a collaborative effort primarily driven by three organizations:

  1. IBM Security (X-Force): Provides foundational threat intelligence and expertise in cybersecurity.
  2. Packet Clearing House (PCH): Offers the extensive global network infrastructure (using Anycast technology, discussed later) that ensures Quad9 is fast and accessible worldwide. PCH is a non-profit focused on operational support and analysis for critical internet infrastructure.
  3. Global Cyber Alliance (GCA): A non-profit organization dedicated to reducing cyber risk globally. GCA helps coordinate the effort and brings additional threat intelligence partners to the table.

Quad9 itself is operated by the Quad9 Foundation, a Swiss-based non-profit organization. This non-profit status is fundamental to its mission and operational philosophy, emphasizing public good over commercial interests.

The Core Mission:

Quad9’s primary goal is straightforward: to prevent users from connecting to known malicious domains. By leveraging real-time threat intelligence feeds from numerous security partners, Quad9 identifies domains associated with malware, phishing, spyware, botnets, and other cyber threats. When a user attempts to resolve one of these malicious domains through Quad9, the service intentionally blocks the request, preventing the user’s device from ever establishing a connection with the harmful server.

Key Characteristics:

  • Free: Quad9 is completely free to use for individuals and organizations.
  • Security-Focused: Its primary differentiator is built-in malicious domain blocking.
  • Privacy-Protecting: Quad9 has a strong commitment to user privacy, explicitly stating it does not log personally identifiable information (PII).
  • High Performance: Utilizes a global Anycast network for low latency and high availability.
  • Non-Profit: Governed by a Swiss foundation, ensuring its motivations are aligned with user protection rather than data monetization or advertising.

By acting as a protective intermediary in the DNS resolution process, Quad9 serves as an automated, first line of defense against a significant portion of online threats.

III. How Quad9 Works: The Mechanics of Protection

Understanding the DNS process provides the foundation for grasping Quad9’s operational mechanics. When you configure your device or router to use Quad9’s IP address (9.9.9.9 or its IPv6 equivalent 2620:fe::fe), your DNS queries are routed through Quad9’s global network infrastructure.

Here’s a breakdown of the Quad9 resolution process, highlighting the security layer:

  1. User Request: You attempt to access a domain, say malicious-site.example.
  2. Query to Quad9: Your device sends the DNS query for malicious-site.example to the nearest Quad9 server (thanks to Anycast routing).
  3. Threat Intelligence Check: Before proceeding with the standard DNS lookup, Quad9 performs a crucial step: it checks the requested domain name (malicious-site.example) against its aggregated list of known malicious domains. This list is compiled from multiple threat intelligence providers (including IBM X-Force, GCA partners, and many others – currently over 20 distinct sources).
  4. Decision Point:
    • If the domain is found on the blocklist: Quad9 returns a special NXDOMAIN (Non-Existent Domain) response to your device. This effectively tells your computer, “This domain doesn’t exist,” preventing your browser or application from establishing any connection to the potentially harmful IP address associated with it. You are protected.
    • If the domain is NOT found on the blocklist: Quad9 considers it safe (based on its current intelligence) and proceeds with the standard recursive DNS lookup process described earlier (querying root, TLD, and authoritative servers) to find the legitimate IP address.
  5. Response to User (for safe domains): Once Quad9 obtains the IP address for a safe domain, it caches the result (for speed) and sends the IP address back to your device.
  6. Connection (for safe domains): Your browser uses the received IP address to connect to the intended website or service.

The Power of Aggregated Threat Intelligence:

The effectiveness of Quad9 hinges on the quality and breadth of its threat intelligence. By integrating data from numerous reputable cybersecurity organizations and open-source feeds, Quad9 gains a comprehensive view of the threat landscape. These feeds identify domains involved in various malicious activities:

  • Hosting malware or ransomware.
  • Conducting phishing attacks (fake login pages, etc.).
  • Distributing spyware or potentially unwanted programs (PUPs).
  • Acting as Command and Control (C&C) servers for botnets.
  • Hosting exploit kits that probe browser vulnerabilities.

This aggregation means Quad9 isn’t reliant on a single source, increasing the likelihood of identifying and blocking emerging threats quickly. The intelligence is constantly updated, ensuring the blocklist remains current.

Recursive Resolution:

It’s important to remember that Quad9 is a recursive DNS provider. It performs the full lookup process on your behalf for domains it deems safe. It doesn’t just block; it also resolves legitimate domains, acting as your complete DNS service.

IV. The Shield of Quad9: Key Protection Features Detailed

Quad9’s core value lies in the specific types of threats it automatically neutralizes at the DNS level. Let’s explore these protections in more detail:

1. Malware Blocking:

  • What it is: Malware (malicious software) includes viruses, worms, Trojans, ransomware, and other software designed to harm or infiltrate computer systems. It often spreads through malicious websites, infected downloads, or compromised links.
  • How Quad9 Protects: Many malware campaigns rely on users visiting specific domains to download the malicious payload or for the malware already on a system to “call home” to its operator. Quad9 blocks access to domains known to host malware installers, drive-by download sites (which attempt to install malware automatically upon visiting), and domains used by malware for communication or updates. By preventing the initial connection, Quad9 can stop malware infections before they even start or disrupt the operation of existing infections.
    • Example: You click a link that leads to download-virus-here.xyz. Quad9 identifies this domain as malicious and returns NXDOMAIN, preventing your browser from ever reaching the site and downloading the virus.

2. Phishing Protection:

  • What it is: Phishing involves tricking users into revealing sensitive information (like usernames, passwords, credit card numbers) by impersonating legitimate entities. This is often done via emails or messages containing links to fake login pages or websites designed to look like banks, social media platforms, or other trusted services.
  • How Quad9 Protects: Phishing attacks rely entirely on users visiting fraudulent domains. Quad9 maintains lists of domains identified as being used for phishing campaigns. When you inadvertently click a phishing link (e.g., yourbank-secure-login.info instead of the real bank site), Quad9 blocks the DNS resolution, preventing your browser from loading the fake page. This effectively neutralizes the threat before you have a chance to enter your credentials.
    • Example: You receive an email claiming to be from your email provider, asking you to verify your account at webmail-update.biz. Quad9 recognizes this as a phishing domain and blocks it. Your browser shows an error instead of the fake login form.

3. Spyware and Adware Blocking (Limited Scope):

  • What it is: Spyware secretly monitors user activity and collects data without consent. Adware displays unwanted advertisements, sometimes aggressively. While distinct, both often rely on specific domains for installation, communication, or ad delivery.
  • How Quad9 Protects: Quad9 blocks domains known to be directly involved in the distribution or operation of spyware and particularly malicious forms of adware. It’s crucial to note, however, that Quad9 is not primarily an ad-blocker. It does not aim to block domains serving legitimate advertisements. Its focus remains on security threats. While some intrusive ad networks or those closely tied to malware distribution might get blocked, users seeking comprehensive ad-blocking should use dedicated browser extensions or other solutions alongside Quad9.

4. Botnet Command & Control (C&C) Blocking:

  • What it is: A botnet is a network of compromised computers (bots) controlled remotely by an attacker (the botmaster). These bots are often used for large-scale attacks like Distributed Denial of Service (DDoS), sending spam, or stealing data. Bots need to communicate with C&C servers to receive instructions and exfiltrate data.
  • How Quad9 Protects: Quad9 actively blocks domains known to function as C&C servers for botnets. If a device on your network becomes infected and tries to contact its C&C server via a domain name lookup, Quad9 will block that resolution. This can effectively sever the connection between the bot and the botmaster, potentially disabling the malware or preventing it from participating in malicious activities or receiving further instructions. This is a powerful mitigation technique, especially in environments with many devices (like businesses or smart homes).
    • Example: A compromised smart thermostat on your network tries to resolve botnet-control-panel.info to receive attack commands. Quad9 blocks the request, preventing the thermostat from participating in a DDoS attack.

5. Exploit Kit Protection:

  • What it is: Exploit kits are sophisticated tools hosted on compromised or malicious websites. When a user visits such a site, the kit automatically probes their browser and plugins (like Flash, Java, PDF readers) for known vulnerabilities. If a vulnerability is found, the kit delivers malware tailored to exploit it.
  • How Quad9 Protects: Exploit kits often reside on specific domains or use domains to redirect victims. Quad9 blocks access to domains known to host exploit kits or act as gateways to them. By preventing the initial connection to the exploit kit’s landing page, Quad9 stops the vulnerability probing process before it can begin.

The Importance of DNS-Level Blocking:

Blocking threats at the DNS level is efficient and effective for several reasons:

  • Early Intervention: It stops the connection before any potentially harmful data is exchanged between your device and the malicious server.
  • Network-Wide Protection: If configured on your router, Quad9 protects all devices on your network (computers, phones, tablets, IoT devices) without needing to install software on each one.
  • Low Resource Usage: The blocking happens remotely on Quad9’s servers, imposing minimal performance overhead on your local devices compared to some software-based filtering solutions.
  • Platform Agnostic: It works regardless of the operating system or browser you use.

However, it’s crucial to understand that Quad9 is not a silver bullet. It complements, but does not replace, other essential security measures like antivirus software, firewalls, regular software updates, and cautious browsing habits. It cannot block threats delivered via direct IP connections (though this is less common for initial infection vectors) or threats that don’t rely on DNS lookups for malicious domains (like malware spread via USB drives).

V. Beyond Blocking: Privacy as a Cornerstone

In an era of increasing concern over digital surveillance and data commodification, Quad9 distinguishes itself with a strong commitment to user privacy. This is not merely a marketing point; it’s embedded in its operational philosophy and governance structure as a non-profit organization.

No Logging of Personal Data:

Quad9’s privacy policy is explicit: it does not collect or store any personally identifiable information (PII) about its users. This means:

  • No IP Address Logging: Quad9 does not permanently store the IP address from which your DNS queries originate. This is a critical distinction from many ISP DNS providers and even some other public DNS services, which may log IP addresses for various purposes (analytics, security monitoring, commercial profiling).
  • No Correlation: Since IP addresses aren’t stored, Quad9 cannot correlate specific DNS queries (which websites you are trying to visit) with specific users or households.
  • No Query Logging Tied to You: While Quad9 does collect anonymized, aggregate data about domain lookups (e.g., how many times example.com was requested globally, or telemetry about threat types blocked), this data is stripped of any information that could link it back to an individual user or their IP address.

Anonymization Techniques:

Quad9 employs techniques to ensure the data it does need for operational purposes (like understanding traffic patterns, identifying network issues, or measuring threat blocking effectiveness) is properly anonymized. This typically involves aggregation and removing source IP information before any analysis or storage occurs.

Compliance and Governance:

Operating under Swiss jurisdiction provides Quad9 with a strong legal framework for privacy protection. Switzerland has robust data protection laws. Furthermore, as a non-profit, Quad9’s primary fiduciary duty is to the public and its mission, not to shareholders demanding data monetization. This structure inherently aligns its interests with user privacy.

Contrast with ISP DNS:

Your ISP’s default DNS resolver often presents a significant privacy concern. ISPs can, and often do, log your DNS queries. This data can reveal:

  • Which websites you visit.
  • Which apps you use (as they often make DNS queries).
  • Potentially sensitive information about your interests, habits, and online activities.

This data can be used for targeted advertising, sold to third-party data brokers, or provided to government agencies. Some ISPs even engage in “DNS hijacking,” redirecting NXDOMAIN responses to their own search or advertising pages. By using Quad9, you opt out of this potential surveillance and data collection by your ISP at the DNS level.

Contrast with Other Public DNS Providers:

While other large public DNS providers like Google (8.8.8.8) and Cloudflare (1.1.1.1) also offer strong performance and varying degrees of privacy commitments, their business models differ from Quad9’s.

  • Google: While Google Public DNS has a privacy policy stating logs are anonymized after 24-48 hours, Google’s core business is advertising and data analytics. Users may have concerns about how even anonymized DNS data might fit into Google’s broader data ecosystem.
  • Cloudflare: Cloudflare has a strong privacy focus for its 1.1.1.1 service, promising to delete query logs within 24 hours and working with third-party auditors. However, Cloudflare is a large, for-profit company with a wide range of commercial services. Its primary focus for 1.1.1.1 is often positioned around speed and privacy, with security filtering offered as separate or secondary options (e.g., 1.1.1.2 for malware blocking).

Quad9’s unique position as a non-profit solely dedicated to security and privacy through DNS provides a level of assurance that commercial entities may find harder to match, as there is no underlying profit motive tied to user data.

Encrypted DNS (DoT/DoH):

Quad9 further enhances privacy by strongly supporting encrypted DNS protocols: DNS-over-TLS (DoT) and DNS-over-HTTPS (DoH). These protocols encrypt your DNS queries between your device and Quad9’s servers, preventing eavesdropping by anyone on the network path (including your ISP or operators of public Wi-Fi hotspots). We will discuss DoT and DoH in more detail in the Advanced Features section.

In summary, Quad9’s privacy stance is a core feature, offering users a way to significantly reduce their DNS-related data footprint and shield their browsing habits from surveillance by ISPs and potentially other third parties.

VI. Performance Considerations: Speed and Reliability

While security and privacy are Quad9’s primary drivers, performance remains a critical factor for any DNS service. Slow DNS resolution translates directly to slower webpage loading times and a sluggish internet experience. Quad9 is engineered for high performance and reliability.

Global Anycast Network:

Quad9 leverages the extensive global network infrastructure provided by Packet Clearing House (PCH). This network utilizes Anycast routing. Here’s how Anycast works and why it’s beneficial:

  • Single IP, Multiple Locations: Quad9’s primary IP address (9.9.9.9) is announced from numerous data centers (Points of Presence or PoPs) spread across the globe. Currently, Quad9 has servers in hundreds of cities across over 90 countries.
  • Automatic Routing to Nearest Server: When you send a DNS query to 9.9.9.9, internet routing protocols automatically direct your request to the geographically or topologically closest Quad9 server available to you.
  • Benefits:
    • Low Latency: By resolving your queries at a nearby server, the round-trip time for the DNS request is minimized, leading to faster lookups and quicker page loads.
    • High Availability & Resilience: If one Quad9 server or location experiences an outage or becomes overloaded, traffic is automatically rerouted to the next nearest operational server. This makes the service highly resilient to failures and ensures consistent availability.
    • Load Distribution: Traffic is naturally distributed across the global network, preventing any single location from becoming a bottleneck.

Impact on Latency:

For most users, switching to Quad9 from their default ISP DNS can often result in either comparable or noticeably faster DNS resolution times. This is because:

  • ISPs may not invest as heavily in optimizing their DNS infrastructure or may have fewer server locations compared to PCH’s global footprint.
  • Quad9’s servers are typically well-provisioned and focused solely on efficient DNS resolution (and security filtering).

However, actual performance can vary depending on several factors:

  • Your Geographic Location: How close are you to the nearest Quad9 PoP versus your ISP’s DNS server?
  • Your ISP’s Peering: How efficiently does your ISP route traffic towards Quad9’s network?
  • ISP DNS Caching: ISPs sometimes have very large caches, which might make lookups for extremely popular domains slightly faster if queried frequently within their network.

Independent DNS performance monitoring services (like DNSPerf) consistently rank Quad9 among the top performers globally, often trading places with Cloudflare and Google Public DNS depending on the region and metric being measured.

Reliability and Uptime:

Thanks to the Anycast network’s inherent redundancy and the operational expertise of PCH, Quad9 boasts excellent uptime and reliability. Service disruptions are rare and typically localized, with traffic automatically failing over to other nodes. This makes Quad9 a dependable choice for users who need consistent internet access.

In conclusion, users adopting Quad9 can generally expect high performance and robust reliability, often meeting or exceeding the speed of their default ISP DNS, while simultaneously gaining significant security and privacy benefits.

VII. Quad9 vs. The World: A Comparative Look

Choosing a DNS resolver involves weighing different priorities: security, privacy, speed, filtering options, and ease of use. Let’s compare Quad9 to other common alternatives:

1. Your ISP’s Default DNS:

  • Pros: Requires no setup; usually configured automatically when you connect. May have good peering within the ISP’s network.
  • Cons:
    • Privacy: High potential for logging user browsing habits for commercial or other purposes.
    • Security: Typically offers no malicious domain filtering.
    • Censorship/Redirection: Some ISPs may block certain domains based on legal requirements or commercial decisions, or hijack NXDOMAIN responses.
    • Performance: Can be variable; often not as globally optimized as public DNS services.
  • Quad9 Advantage: Superior security (blocking), vastly better privacy (no PII logging), often better performance due to Anycast, non-profit ethos.

2. Google Public DNS (8.8.8.8 / 8.8.4.4):

  • Pros: Generally very fast and reliable due to Google’s massive infrastructure. Widely known and easy to remember. Strong infrastructure security.
  • Cons:
    • Privacy: While Google has a privacy policy, its core business relies on data. Concerns persist about how DNS data (even anonymized) might integrate with other Google services or user profiles over time. Logs are kept for 24-48 hours before anonymization.
    • Security Filtering: Does not offer malicious domain blocking by default. It focuses purely on resolution speed and accuracy.
  • Quad9 Advantage: Built-in security filtering is the primary difference. Quad9’s non-profit status and stronger privacy policy (no PII logging at all) offer greater assurance against data usage. Performance is often comparable.

3. Cloudflare DNS (1.1.1.1 / 1.0.0.1):

  • Pros: Extremely fast, often topping performance charts. Strong focus on privacy with a clear policy (logs deleted within 24 hours, third-party audits). Supports modern protocols like DoT and DoH extensively. Offers separate IPs for malware blocking (1.1.1.2) and malware+adult content blocking (1.1.1.3).
  • Cons:
    • Security Filtering: Default service (1.1.1.1) does not block malicious domains; users must explicitly choose 1.1.1.2 for that feature. The threat intelligence sources might differ from Quad9’s broader aggregation.
    • Commercial Entity: As a large, for-profit company, its long-term motivations might be perceived differently than a non-profit’s, although its current privacy stance is strong.
  • Quad9 Advantage: Security filtering is enabled by default on the primary 9.9.9.9 address. Quad9 aggregates threat intelligence from a potentially wider range of specialized security partners. The non-profit structure provides a different kind of trust model.

4. OpenDNS (Cisco Umbrella) (208.67.222.222 / 208.67.220.220):

  • Pros: Long-standing public DNS provider (now owned by Cisco). Offers free tiers (OpenDNS Home) with optional content filtering categories (e.g., blocking adult sites, social media) in addition to basic security filtering. Paid tiers (Cisco Umbrella) offer extensive enterprise features.
  • Cons:
    • Privacy: Free OpenDNS Home requires account creation for customization and may involve more data logging than Quad9 or Cloudflare. Cisco is a commercial entity.
    • Performance: While generally reliable, performance may not always match the top tier (Google, Cloudflare, Quad9).
    • Security Focus: While offering security, its feature set often leans towards broader content filtering, whereas Quad9’s primary focus is strictly on cybersecurity threats.
  • Quad9 Advantage: Stronger default privacy (no PII logging, no account needed for core service). Focused purely on security threats rather than content filtering. Non-profit status. Often better performance in benchmarks.

Quad9’s Unique Selling Proposition:

Quad9 carves out a unique niche by combining:

  • Default, Robust Security: Blocking is on by default, leveraging a wide array of threat intelligence.
  • Uncompromising Privacy: A clear, strong privacy policy backed by non-profit governance and Swiss jurisdiction.
  • High Performance: Competitive speeds thanks to a global Anycast network.
  • Simplicity: Easy to set up and use the core service (9.9.9.9).

For users prioritizing automated security and strong privacy without sacrificing performance, Quad9 presents a compelling choice.

VIII. Setting Up Quad9: Step-by-Step Implementation

Switching your devices to use Quad9 is usually a straightforward process. You can configure it at two main levels:

  1. On your Router: This is the recommended method for home networks, as it automatically protects all devices connected to your Wi-Fi (computers, phones, tablets, smart TVs, IoT gadgets) without needing individual configuration.
  2. On Individual Devices: Useful if you can’t change router settings (e.g., on public Wi-Fi, cellular network, or if you only want specific devices protected). Settings on an individual device typically override the router’s settings for that device.

Quad9 DNS Addresses:

You’ll need these IP addresses:

  • Primary IPv4: 9.9.9.9
  • Secondary IPv4: 149.112.112.112 (Provides redundancy if the primary is unreachable)
  • Primary IPv6: 2620:fe::fe
  • Secondary IPv6: 2620:fe::9 (Provides redundancy for IPv6)

(Note: Quad9 also offers an “unsecured” service without blocking at 9.9.9.10 / 149.112.112.10 / 2620:fe::10 / 2620:fe::11, and a service with ECS support described later, but for standard protection, use the primary addresses listed above).

General Steps (Consult Your Specific Device/Router Manual):

A. Configuring on a Router:

  1. Access Router Settings: Open a web browser and enter your router’s IP address (commonly 192.168.1.1, 192.168.0.1, or 10.0.0.1 – check your router’s manual or label). Log in with your administrator username and password.
  2. Find DNS Settings: Look for sections named “Network Settings,” “Internet,” “WAN,” or “DHCP Server.” Within these, find the “DNS Server” settings.
  3. Enter Quad9 Addresses: Change the settings from “Automatic” or “Get from ISP” to “Manual” or “Use these DNS Servers.” Enter 9.9.9.9 as the Primary (or DNS1) and 149.112.112.112 as the Secondary (or DNS2). If IPv6 settings are available and enabled on your network, enter 2620:fe::fe as the Primary IPv6 DNS and 2620:fe::9 as the Secondary IPv6 DNS.
  4. Save and Reboot: Save or apply the changes. It’s often a good idea to reboot your router and then restart your connected devices (or disconnect/reconnect them from Wi-Fi) to ensure they pick up the new DNS settings via DHCP.

B. Configuring on Windows 10/11:

  1. Open Network Settings: Right-click the Network icon in the system tray (Wi-Fi or Ethernet) and select “Open Network & Internet settings.”
  2. Change Adapter Options: Click on “Change adapter options.”
  3. Select Connection: Right-click on your active network connection (e.g., “Wi-Fi” or “Ethernet”) and choose “Properties.”
  4. Configure IP Settings:
    • Select “Internet Protocol Version 4 (TCP/IPv4)” and click “Properties.”
    • Select “Use the following DNS server addresses.”
    • Enter 9.9.9.9 in “Preferred DNS server” and 149.112.112.112 in “Alternate DNS server.”
    • Click “OK.”
    • (Optional – If using IPv6) Select “Internet Protocol Version 6 (TCP/IPv6)” and click “Properties.” Select “Use the following DNS server addresses.” Enter 2620:fe::fe in “Preferred” and 2620:fe::9 in “Alternate.” Click “OK.”
  5. Close Windows: Click “Close” on the connection properties window. You might need to flush your DNS cache (open Command Prompt as admin and type ipconfig /flushdns).

C. Configuring on macOS:

  1. Open System Preferences/Settings: Go to the Apple Menu > System Preferences (older macOS) or System Settings (newer macOS).
  2. Network Pane: Click on “Network.”
  3. Select Connection: Select your active network connection (e.g., “Wi-Fi” or “Ethernet”) from the left sidebar.
  4. Advanced/Details: Click the “Advanced…” button (older macOS) or the “Details…” button next to your connection (newer macOS).
  5. DNS Tab: Go to the “DNS” tab.
  6. Add Quad9 Addresses: Click the + button under “DNS Servers” to add new servers. Enter 9.9.9.9 and press Enter. Click + again and enter 149.112.112.112. If you have IPv6 enabled, also add 2620:fe::fe and 2620:fe::9. You can remove any existing greyed-out DNS servers provided by your ISP by selecting them and clicking the - button (if necessary).
  7. Apply Changes: Click “OK” and then “Apply.”

D. Configuring on Linux (NetworkManager Example):

  • GUI Method: Use your distribution’s Network Settings tool. Select your connection, go to IPv4 settings, change Method to “Automatic (DHCP) addresses only” or similar, and enter 9.9.9.9, 149.112.112.112 in the DNS servers field (comma-separated). Do similarly for IPv6 if needed (2620:fe::fe, 2620:fe::9). Save and reconnect.
  • Command Line (nmcli): Find your connection name (nmcli con show). Then modify it (replace MyConnection):
    bash
    sudo nmcli con mod MyConnection ipv4.dns "9.9.9.9 149.112.112.112"
    sudo nmcli con mod MyConnection ipv4.ignore-auto-dns yes
    # Optionally for IPv6
    sudo nmcli con mod MyConnection ipv6.dns "2620:fe::fe 2620:fe::9"
    sudo nmcli con mod MyConnection ipv6.ignore-auto-dns yes
    # Reactivate connection
    sudo nmcli con down MyConnection && sudo nmcli con up MyConnection
  • systemd-resolved: Edit /etc/systemd/resolved.conf, uncomment and set DNS=9.9.9.9 149.112.112.112 and FallbackDNS= (leave empty or set others). Add Domains=~. to ensure resolved uses these servers globally. Restart systemd-resolved.service.

E. Configuring on iOS (iPhone/iPad):

  1. Open Settings: Go to “Settings” > “Wi-Fi.”
  2. Select Network: Tap the ‘i’ icon next to the Wi-Fi network you are connected to.
  3. Configure DNS: Scroll down and tap “Configure DNS.”
  4. Manual: Select “Manual.”
  5. Add Servers: Tap “Add Server” and enter 9.9.9.9. Tap “Add Server” again and enter 149.112.112.112. If IPv6 is active, add 2620:fe::fe and 2620:fe::9.
  6. Remove Old Servers: You can delete any existing servers by tapping the red minus icon and then “Delete.”
  7. Save: Tap “Save” in the top right corner. (Note: This setting is per Wi-Fi network).

F. Configuring on Android:

  • Method 1: Private DNS (Android 9 Pie and later – Recommended): This uses encrypted DNS (DoT).
    1. Go to Settings > Network & internet (or Connections) > Private DNS (may be under Advanced or More connection settings).
    2. Select “Private DNS provider hostname.”
    3. Enter dns.quad9.net
    4. Tap “Save.” This setting applies to both Wi-Fi and Mobile Data.
  • Method 2: Per Wi-Fi Network (Older Android or if Private DNS isn’t preferred):
    1. Go to Settings > Wi-Fi.
    2. Long-press on your connected network and choose “Modify network” or tap the gear/settings icon.
    3. Show advanced options (if necessary).
    4. Change “IP settings” from “DHCP” to “Static.”
    5. The current IP address, gateway, etc., will be shown. Do not change these unless you know what you’re doing.
    6. Find the “DNS 1” and “DNS 2” fields. Enter 9.9.9.9 in DNS 1 and 149.112.112.112 in DNS 2.
    7. Save the settings. (Note: This setting is per Wi-Fi network).

Verification:

After changing your DNS settings, you can verify they are active:

  1. Quad9 Test Page: Visit https://on.quad9.net/. This page will tell you if you are currently using the Quad9 network. It can also indicate if you are using specific features like security blocking or ECS.
  2. DNS Leak Test: Use websites like dnsleaktest.com. Run the standard test. The results should show Quad9 or Packet Clearing House servers, not your ISP’s servers.

IX. Advanced Quad9 Features: Enhancing Security and Privacy

Beyond the standard DNS resolution over UDP/TCP port 53, Quad9 supports modern, encrypted DNS protocols and offers variations of its service.

1. DNS-over-TLS (DoT):

  • What it is: DoT encrypts your DNS queries using the Transport Layer Security (TLS) protocol – the same encryption used by HTTPS websites. It runs over a dedicated port, typically TCP port 853.
  • Benefits:
    • Confidentiality: Prevents eavesdropping on your DNS queries by anyone on the network path (ISP, public Wi-Fi operators). They cannot see which websites you are trying to resolve.
    • Integrity: Protects against manipulation or modification of DNS responses in transit.
  • Quad9 DoT Address: dns.quad9.net (Use this hostname in clients supporting DoT, like Android’s Private DNS feature).
  • Setup: Supported natively in Android 9+, iOS 14+, macOS 11+, Windows 11 (via settings), and various Linux configurations (e.g., using systemd-resolved or stubby).

2. DNS-over-HTTPS (DoH):

  • What it is: DoH also encrypts DNS queries, but it wraps them within standard HTTPS traffic (using TCP port 443).
  • Benefits:
    • Confidentiality & Integrity: Same benefits as DoT.
    • Network Bypass: Because DoH traffic looks like regular web traffic (HTTPS on port 443), it’s much harder for networks to block or filter compared to DoT on port 853. This can be useful on restrictive networks.
  • Quad9 DoH Address: https://dns.quad9.net/dns-query (Use this URL in DoH-compatible clients, like Firefox, Chrome, or Windows 11).
  • Controversy: DoH has faced some controversy, with concerns that it could bypass network-level security policies or parental controls implemented via traditional DNS filtering, and potentially centralize more internet traffic through large application providers (like browser vendors) if they default to specific DoH resolvers. However, when manually configured by the user to point to a trusted resolver like Quad9, it provides significant privacy benefits.
  • Setup: Supported natively in major browsers (Firefox, Chrome, Edge), Windows 11, iOS 14+, macOS 11+, and various Linux tools.

Using DoT or DoH with Quad9 is highly recommended for maximizing privacy and security, especially on untrusted networks.

3. ECS (EDNS Client Subnet):

  • What it is: ECS is a DNS extension that allows recursive resolvers to send a portion of the user’s IP address (their client subnet) to authoritative nameservers. The goal is to help Content Delivery Networks (CDNs) provide more accurate geographic responses, directing users to the nearest content server for better performance.
  • Privacy Implications: Sending even part of a user’s IP address raises privacy concerns, as it leaks location information further down the DNS chain.
  • Quad9’s Approach: Quad9’s primary services (9.9.9.9, dns.quad9.net) do not send ECS data to authoritative servers, prioritizing user privacy over potential minor CDN performance gains.
  • Optional ECS Service: For users who absolutely need ECS (e.g., encountering issues with specific geo-located services), Quad9 provides a separate set of resolver addresses that do include ECS support:
    • IPv4: 9.9.9.11 / 149.112.112.11
    • IPv6: 2620:fe::11 / 2620:fe::10
    • DoT Hostname: dns11.quad9.net
    • DoH URL: https://dns11.quad9.net/dns-query
    • Recommendation: Only use the ECS-enabled service if you have a specific, verifiable need. For most users, the default non-ECS service offers better privacy.

By offering these advanced protocols and service variations, Quad9 allows users to tailor their DNS setup for enhanced security, privacy, and compatibility based on their specific needs and technical capabilities.

X. The Non-Profit Advantage: Trust and Transparency

Quad9’s status as a non-profit organization, governed by the Swiss-based Quad9 Foundation, is more than just a structural detail; it’s central to its value proposition and the trust users place in it.

Funding Model:

Quad9 is funded through a combination of sources:

  • Donations: Contributions from individuals and organizations who support its mission.
  • Grants: Funding from foundations or other entities interested in promoting internet security and privacy.
  • In-Kind Support: Significant contributions from its partners, such as the network infrastructure from PCH and threat intelligence from IBM and GCA partners.

This model means Quad9 is not beholden to commercial pressures that might conflict with user interests, such as:

  • Data Monetization: There is no incentive to collect, analyze, or sell user data for advertising or other commercial purposes.
  • Upselling: Quad9 doesn’t need to push users towards paid tiers with more features, as its core mission is to provide robust protection freely.

Motivation: Public Good vs. Profit:

The driving force behind Quad9 is the desire to improve the security and privacy of the internet ecosystem for everyone. Its partners (IBM, PCH, GCA) initiated the project as a way to leverage their capabilities for the public good. This mission-driven approach fosters trust, as users can be more confident that decisions are made in favor of protection and privacy rather than profit maximization.

Transparency:

While specific operational details or threat intelligence sources might remain confidential for security reasons, Quad9 aims for transparency in its policies and operations. Its privacy policy is clear, and its non-profit status requires adherence to governance standards. This contrasts with potentially less transparent data handling practices at some commercial entities or ISPs. The Swiss jurisdiction also provides a legal framework known for strong data protection principles.

The non-profit structure underpins Quad9’s commitment to being a neutral, trustworthy guardian at the DNS layer, focused solely on protecting its users.

XI. Addressing Concerns and Criticisms

While Quad9 offers significant benefits, it’s important to have a balanced view and acknowledge potential concerns or criticisms:

1. False Positives (Overblocking):

  • Issue: Like any blocklist-based system, there’s a possibility that Quad9 might occasionally block a legitimate domain mistakenly (a “false positive”). This could happen if a domain was briefly compromised and added to a threat feed, or if threat intelligence is inaccurate.
  • Impact: Users might be unable to access a needed website or service.
  • Mitigation: Quad9 uses multiple threat intelligence sources and likely employs validation mechanisms to minimize false positives. They also provide mechanisms for users and domain owners to report potential false positives for review and correction. If encountering a suspected false positive, users can temporarily switch to the non-blocking Quad9 service (9.9.9.10) or another DNS provider to access the site, and report the issue to Quad9.

2. Performance Variability:

  • Issue: While generally fast, Quad9’s performance relative to other DNS providers (especially ISP DNS) can depend heavily on the user’s geographic location, ISP peering arrangements, and network conditions. In some specific locations, another provider might offer slightly lower latency.
  • Mitigation: Quad9 continuously expands its Anycast network footprint to improve global coverage and reduce latency. Users experiencing performance issues can test other providers (like Cloudflare or Google) to see if they offer better results for their specific connection.

3. Legal Challenges (Sony Music Injunction):

  • Issue: In 2021, Sony Music obtained a court injunction in Germany requiring Quad9 (specifically, its German servers) to block DNS resolution for a domain allegedly involved in copyright infringement (a music piracy site). This marked a significant, controversial case where a DNS resolver was compelled to block content for reasons other than cybersecurity threats.
  • Impact: Quad9 complied with the legally binding order within Germany but contested the ruling, arguing that recursive DNS providers are neutral infrastructure conduits and should not be responsible for policing content or copyright infringement at the DNS level. They appealed the decision, emphasizing the dangerous precedent it could set for internet freedom and the potential for abuse (e.g., forcing DNS providers to block political speech or competitors). The case highlighted the legal complexities and pressures facing infrastructure providers.
  • Quad9’s Stance: Quad9 firmly maintains that its mission is cybersecurity, not content policing. It fights against such rulings where possible, advocating for the neutrality of DNS infrastructure. This incident underscores Quad9’s commitment to its principles but also reveals the legal battles such services might face.

4. Not a Complete Security Solution:

  • Issue: Users might mistakenly believe that using Quad9 makes them immune to all online threats.
  • Reality: Quad9 is a powerful layer of security, but it’s not a standalone solution. It primarily blocks threats associated with malicious domains. It cannot protect against:
    • Malware delivered via other means (USB drives, direct file downloads from legitimate-but-compromised sites not yet on blocklists).
    • Attacks using direct IP addresses.
    • Phishing attacks hosted on legitimate platforms (e.g., a fraudulent form created using Google Docs).
    • Vulnerabilities in your operating system, browser, or applications.
    • Social engineering attacks that don’t involve clicking a known-bad link.
  • Recommendation: Quad9 should always be used in conjunction with other security best practices: reputable antivirus/anti-malware software, a firewall, keeping all software updated, using strong unique passwords and multi-factor authentication, and practicing cautious online behavior.

Understanding these points allows for realistic expectations and highlights the importance of a multi-layered security approach.

XII. The Future of Quad9

The internet threat landscape is constantly evolving, and Quad9 is positioned to adapt and grow:

  • Network Expansion: Continued build-out of the Anycast network to improve performance and reach in underserved regions.
  • Threat Intelligence Enhancement: Integrating new, high-quality threat feeds and refining validation processes to improve blocking accuracy and reduce false positives.
  • Protocol Adoption: Staying current with emerging DNS standards and security protocols.
  • Advocacy: Continuing to advocate for DNS neutrality and resist attempts to force DNS resolvers into roles beyond technical resolution and cybersecurity (like broad content policing).
  • Community Engagement: Fostering relationships with users, researchers, and partners to better understand needs and threats.

As a non-profit focused on a critical aspect of internet infrastructure, Quad9’s future likely involves deepening its commitment to providing free, secure, and private DNS resolution as a fundamental building block for a safer internet.

XIII. Conclusion: Why Choose Quad9?

In the complex and often perilous digital world, Quad9 offers a simple yet remarkably effective way to enhance your online security and privacy. By acting as an intelligent gatekeeper for your DNS requests, it automatically blocks access to a vast number of known malicious destinations – sites hosting malware, phishing scams, botnet C&C servers, and more – before they ever reach your devices.

Key Takeaways:

  • Automated Security: Quad9 provides a free, set-and-forget layer of protection against common cyber threats by blocking malicious domains.
  • Robust Privacy: Governed by a Swiss non-profit, Quad9 has a strong commitment to user privacy, notably by not logging personally identifiable information like IP addresses.
  • High Performance: Its global Anycast network ensures fast and reliable DNS resolution worldwide.
  • Ease of Use: Simple to configure on routers (for network-wide protection) or individual devices.
  • Enhanced Trust: The non-profit model ensures its motivations are aligned with user protection, not data monetization.
  • Modern Standards: Support for encrypted DNS (DoT/DoH) further secures your queries from eavesdropping.

While not a replacement for comprehensive security software or safe browsing habits, Quad9 significantly raises the bar for baseline protection. It intercepts threats at a fundamental level of internet communication, shielding all connected devices when configured on a router. The trade-offs are minimal – potential rare false positives or slight performance variations in specific locations – while the benefits in terms of automated threat blocking and enhanced privacy are substantial.

Changing your DNS settings to 9.9.9.9 is one of the easiest and most impactful steps you can take to make your internet experience safer. Whether you’re a home user concerned about malware and phishing, a parent wanting basic protection for your family network, or a small business looking for a free security enhancement, Quad9 provides a trustworthy, effective, and free solution. Give it a try, test its effectiveness, and experience the peace of mind that comes from having a dedicated guardian watching over your corner of the internet.

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