Networking & DNSAdvanced

What Is Public DNS? How It Works, Benefits, Setup and Best Providers

Quick Answer Public DNS is a Domain Name System (DNS) resolution service that anyone can use to translate website names, such as example.com, into the IP add...

Bison Technical Team Enterprise IT specialists

Updated 15 Oct 2026 19 min read 0 total views

Structured technical guidanceSafety notes included where requiredSources listed below

Quick Answer

Public DNS is a Domain Name System (DNS) resolution service that anyone can use to translate website names, such as example.com, into the IP addresses computers need to connect to websites. Instead of using only the DNS servers supplied by an Internet Service Provider (ISP), users can configure their computers, phones, or routers to use a public DNS provider such as Google Public DNS, Cloudflare DNS, or Quad9.

Public DNS services can provide an alternative when an ISP's DNS is slow or unreliable. Depending on the provider, they may also offer encrypted DNS queries, DNSSEC validation, or filtering of known malicious domains. However, public DNS does not automatically make your internet connection faster, hide all your browsing activity, or block every malicious website. The right choice depends on performance, privacy, security, filtering requirements, and compatibility with your network.

What Is Public DNS?

DNS stands for Domain Name System. It works like an internet directory, helping devices find the network addresses associated with domain names.

For example, when you enter www.example.com in a browser, your device needs to discover the IP address associated with that hostname before it can connect to the appropriate server. A DNS resolver performs this lookup and returns the requested DNS information.

A public DNS resolver is a DNS resolution service made available for general use. Depending on the provider, it may be free, offer optional paid features, or be part of a broader security service.

Normally, a home router or device uses DNS servers supplied automatically by the ISP. Changing the DNS configuration allows you to use a different resolver without necessarily changing your internet connection or ISP.

Public DNS vs. Private DNS vs. DNS Hosting

Term	Meaning	Typical use
Public DNS resolver	A resolver available for general use.	Resolving website names using Google Public DNS or Cloudflare DNS.
Private or internal DNS	DNS used within an organization or private network, often to resolve internal hostnames.	Finding domain controllers, file servers, printers, and internal applications.
Authoritative DNS hosting	A service that publishes the official DNS records for a domain.	Hosting records for a company's website, email, and other internet services.
Encrypted DNS	A way to protect DNS queries between a client and a resolver using protocols such as DNS over HTTPS or DNS over TLS.	Reducing the ability of others on the network to read or modify DNS traffic in transit.

These terms are related but are not interchangeable. For example, Google Public DNS resolves domain names; it is not the service you use to host your domain's authoritative DNS records.

How Does Public DNS Work?

When you open a website, your device generally follows this process:

You enter a domain name. For example, you enter www.example.com in a browser.
The device checks available cached information. The operating system or browser may already have a valid DNS result, so a new external lookup may not be necessary.
The device contacts its configured DNS resolver. This might be the ISP's resolver, Google Public DNS, Cloudflare DNS, or another service.
The resolver checks its cache. If it has a valid cached answer, it can return that answer without repeating the entire lookup.
The resolver obtains the answer if necessary. It can query the DNS hierarchy, including root, top-level-domain, and authoritative name servers, to find the requested record.
The answer is returned and cached where appropriate. The device receives the DNS result and uses the returned address to connect to the website.

DNS records commonly include A records for IPv4 addresses, AAAA records for IPv6 addresses, CNAME records for aliases, and MX records for mail routing. The requested record type determines what information is returned.

DNS caching helps avoid repeating the same lookups. Records are cached according to their time to live (TTL), which specifies how long a result may be retained. Public DNS providers may also use distributed infrastructure and traffic routing to serve queries efficiently.

Benefits of Using Public DNS

1. Potentially Faster DNS Lookups

A well-performing public resolver may return cached results faster than the DNS server currently supplied by your ISP. This can help when opening websites that require multiple DNS lookups.

However, DNS resolution is only one part of website performance. Server response time, internet bandwidth, Wi-Fi quality, browser processing, content delivery networks, and congestion can have a much greater impact. Switching DNS will not increase your subscribed internet speed or repair a weak Wi-Fi signal.

2. An Alternative When ISP DNS Has Problems

If websites fail to open by name while the internet connection itself appears to be working, the ISP's DNS resolver may be experiencing a problem. Testing another resolver can help determine whether DNS is involved.

For example, if a website opens when its IP address is used but fails by domain name, DNS may be one possible cause. This test is not conclusive because many websites use multiple addresses, virtual hosting, HTTPS, and content delivery networks.

3. Security Features

Some public DNS providers support DNSSEC validation, which helps validate DNS data that has been digitally signed. This can reduce the risk of accepting certain forged DNS answers, but it does not prove that a website is trustworthy or free from malware.

Some providers also offer optional or built-in filtering for known malicious domains, phishing sites, or other unwanted categories. Filtering policies vary by provider and configuration.

4. Encrypted DNS Queries

Traditional DNS queries are often transmitted without encryption. Providers that support DNS over HTTPS (DoH) or DNS over TLS (DoT) can encrypt the connection between a compatible client and the resolver.

This makes DNS queries harder for other parties on the local network to read or modify in transit. Encryption does not prevent the DNS provider itself from processing the queries, and it does not encrypt all other internet traffic.

5. More Control Over DNS Configuration

Users and administrators can select a resolver based on privacy policies, filtering requirements, reliability, and measured performance. A router can distribute DNS settings to multiple devices, while individual devices can use separate settings when appropriate.

How Many Public DNS Servers Are Available?

There is no fixed, universally maintained number of public DNS providers. Many organizations operate public resolvers, and some providers offer multiple resolver addresses or different profiles for security and content filtering.

Also, the number of IP addresses is not the same as the number of providers. A provider may advertise multiple IPv4 and IPv6 addresses that connect to the same DNS service.

The following are several widely used public DNS services. This is a selection, not a complete list.

Provider	Standard IPv4 addresses	Main purpose and considerations
Google Public DNS	`8.8.8.8` `8.8.4.4`	General-purpose DNS resolution with global infrastructure, DNSSEC support, and encrypted DNS options. It is not designed as a comprehensive malware or family-filtering service.
Cloudflare DNS	`1.1.1.1` `1.0.0.1`	General-purpose resolver focused on speed and privacy. Separate resolver addresses are available for some malware and adult-content filtering options.
Quad9	`9.9.9.9` `149.112.112.112`	Security-oriented resolver that blocks domains associated with threats under its filtering policy. Blocking may occasionally affect a domain that a user needs.
OpenDNS Home	`208.67.222.222` `208.67.220.220`	Provides DNS services with filtering options. Available features and account requirements depend on the product and service configuration.
AdGuard DNS	`94.140.14.14` `94.140.15.15`	Offers DNS options that can filter advertising and tracking domains. Filtering may affect some websites or applications.

Important: Addresses shown here are standard or commonly published resolver addresses for the named services. Providers may also offer IPv6 addresses, encrypted DNS endpoints, and special-purpose profiles. Review each provider's official documentation before deployment, especially in business networks.

Which Public DNS Is Best?

There is no single public DNS provider that is best for every user. The most suitable choice depends on what you want to achieve.

Requirement	Provider to consider	Reason
General browsing and an alternative to ISP DNS	Google Public DNS or Cloudflare DNS	Both offer widely used general-purpose resolvers. Test them on your own connection to compare results.
Blocking known malicious domains	Quad9 or a provider's security-filtering profile	Security-oriented filtering can block some known harmful domains before a connection is made.
Filtering advertising or tracking domains at DNS level	AdGuard DNS or a suitable filtering resolver	Filtering can reduce requests to some advertising or tracking domains, but it will not block every advertisement.
Family-oriented content filtering	A resolver profile specifically designed for family filtering	These profiles may block adult or other selected categories. Confirm the provider's policy and limitations.
Encrypted DNS on compatible devices	A provider that supports DoH or DoT and your device's configuration method	Encrypted DNS protects the query in transit between the device and the resolver.
Business networks with internal servers or domain services	The organization's approved internal DNS service	Internal DNS may be required for Active Directory, private applications, internal hostnames, and network policies.

For ordinary home browsing, Google Public DNS and Cloudflare DNS are reasonable starting points. If security filtering is the priority, compare Quad9 and other providers that explicitly document their blocking policies. If privacy is the priority, review the provider's privacy policy and use an encrypted DNS protocol supported by your device.

Do not assume that two different public DNS providers configured as primary and secondary will always behave as a single consistent service. Operating systems and routers may select either server, and filtering policies or DNS answers can differ. For predictable filtering, use a consistent provider and configuration unless you understand the implications of mixing resolvers.

How to Choose a Public DNS Provider

Consider the following factors before changing your settings:

Performance: Measure DNS response times on your own network instead of relying only on published rankings.
Reliability: Consider the provider's infrastructure, availability information, and whether it offers more than one resolver address.
Privacy: Read the provider's DNS privacy policy to understand what information is collected, retained, and used.
Encryption: Check whether the provider supports DNS over HTTPS or DNS over TLS and whether your device can use it.
Security filtering: Confirm whether malicious-domain blocking is included, optional, or unavailable.
Compatibility: Make sure the resolver works with your ISP, router, VPN, local network, and required applications.
Support requirements: Business networks may require internal DNS, parental controls, auditing, content policies, or other organizational controls.

How to Use Public DNS on Windows 11 and Windows 10

The following steps apply to typical Windows network configurations. Menu names may vary slightly depending on the Windows version and network adapter.

Step 1: Record the Existing DNS Settings

Before making changes, record your current DNS server addresses. If the settings are obtained automatically from the router or ISP, note that as well. This allows you to restore the previous configuration if necessary.

Step 2: Open Network Settings

Open Settings.
Select Network & Internet.
Choose Wi-Fi or Ethernet, depending on your connection.
Open the connection's properties or hardware properties and locate DNS server assignment.
Select Edit and change the setting from automatic to manual, if required.

Step 3: Enter the DNS Addresses

Enable IPv4 and enter the following Google Public DNS addresses:

Preferred DNS: 8.8.8.8
Alternate DNS: 8.8.4.4

Save the changes. If you also configure IPv6, use the provider's official IPv6 addresses for the IPv6 configuration. Do not enter IPv4 addresses into IPv6 fields.

You can use Cloudflare DNS instead by entering 1.1.1.1 and 1.0.0.1, or select another provider's documented addresses.

Step 4: Verify the DNS Server

Open Command Prompt and run the following command to test whether Google Public DNS can resolve a domain:

nslookup example.com 8.8.8.8

This command asks the specified DNS server directly for the address associated with example.com. A successful result should include a DNS response and one or more addresses, depending on the records returned.

To inspect the DNS settings currently reported by Windows, run:

ipconfig /all

Look for the DNS Servers entry under the active network adapter. This helps confirm the adapter's configuration, although browser-specific encrypted DNS settings, VPN software, and other network components may use a different resolver.

How to Use Public DNS on Other Devices

Android

On Android 9 and later, compatible devices can use Private DNS, which supports DNS over TLS.

Open Settings and find Network & Internet, Connections, or the equivalent menu on your device.
Open Private DNS. You may need to search Settings to locate it.
Select the option for a private DNS provider hostname.
For Google Public DNS, enter dns.google.
Save the setting and test browsing.

This hostname is for the encrypted DNS configuration. Do not enter 8.8.8.8 in a field that specifically requests a provider hostname. If connectivity problems begin, return to the Private DNS setting and restore the previous option, such as Automatic.

iPhone and iPad

To configure traditional DNS for a specific Wi-Fi network:

Open Settings and select Wi-Fi.
Tap the information button beside the connected network.
Open Configure DNS and select Manual.
Add the DNS addresses you want to use, such as 8.8.8.8 and 8.8.4.4.
Save the changes and test the connection.

This setting applies to that Wi-Fi network and does not necessarily change DNS for cellular connections. Manual DNS addresses configured this way are not, by themselves, a guarantee of encrypted DNS. For DoH or DoT, use a trusted, compatible configuration method and follow the provider's documentation.

macOS

Open System Settings and select Network.
Select your active Wi-Fi or Ethernet connection.
Open Details and choose DNS.
Add the required resolver addresses, such as 8.8.8.8 and 8.8.4.4.
Apply the changes and test website access.

To undo the change, remove the added addresses and restore the previous DNS configuration.

Linux

On many desktop Linux distributions, DNS is configured through NetworkManager or the distribution's network settings.

Open the network settings and select the active wired or wireless connection.
Open its IPv4 or IPv6 configuration.
Enter the DNS addresses supplied by the chosen provider.
If necessary, change the DNS method so manually entered addresses are used rather than replaced by automatic DHCP settings.
Save or reconnect, then test resolution.

Linux systems vary in how they manage DNS. Files such as /etc/resolv.conf may be generated automatically by system services, so editing them directly may not persist. Follow the documentation for your distribution and network manager.

Router Configuration

Changing DNS on a router can allow multiple connected devices to use the selected resolver automatically, depending on how the router distributes DNS settings.

Sign in to the router's administration interface using its documented management address.
Locate the Internet, WAN, DHCP, or DNS configuration section, depending on the router model.
Record the existing settings.
Enter the chosen provider's DNS addresses in the appropriate fields.
Save the configuration and reconnect devices or renew their network settings if necessary.
Test name resolution on more than one device.

Do not change the router's management IP address when you only intend to change DNS. Some routers receive DNS settings automatically from the ISP, and some ISP-managed routers restrict this option.

How to Test and Compare Public DNS Performance

DNS response time is one useful measurement, but a single test is not enough to determine which provider is best for your connection.

On Windows, you can query a domain directly against two resolvers:

nslookup example.com 8.8.8.8
nslookup example.com 1.1.1.1

Compare the reported response times if available. Repeat the tests with several commonly used domains and more than one attempt. A result can be affected by cache state, network latency, routing, and the time of testing.

For a more complete comparison, consider:

Whether lookups consistently succeed.
Response times across multiple domains.
Whether websites load correctly after DNS resolution.
Whether security or content filtering blocks sites you need.
Whether the provider supports the privacy and encryption features you require.

A direct nslookup test confirms that the specified server answered that query. It does not prove that every application, browser, VPN, or device is using the same DNS resolver.

Illustrative Case Study: Websites Are Slow to Open

Scenario: Employees in a small office report that some websites take a long time to begin loading, but file downloads are otherwise normal. The IT technician suspects that DNS resolution may be contributing to the delay.

The technician confirms that the internet connection is stable and checks whether the problem affects multiple devices.
The technician records the existing DNS settings and tests several domains against the current resolver.
The same domains are queried against Google Public DNS and Cloudflare DNS, using the same office connection.
The technician compares response consistency and then tests actual website loading, not just DNS query time.
If a different resolver performs better and the sites continue to work correctly, the technician can trial the new configuration. If there is no meaningful improvement, the original settings are restored and other causes are investigated.

This is an illustrative troubleshooting scenario, not a report of measured results. It shows how public DNS can be evaluated as one possible cause without assuming that DNS is responsible for every slow website.

Limitations and Common Misunderstandings

Public DNS Does Not Increase Internet Bandwidth

DNS resolves names; it does not upgrade your internet plan, improve a weak Wi-Fi signal, or remove network congestion. It may reduce lookup delays, but the overall speed improvement can be small or unnoticeable.

Public DNS Is Not a VPN

Changing DNS does not route all your internet traffic through a VPN tunnel. A DNS resolver can see the domain names you query, and your ISP may still observe the IP addresses you connect to and other network metadata. Encrypted DNS protects DNS traffic between your device and the resolver but does not provide the same functions as a VPN.

Public DNS Does Not Automatically Block Malware

General-purpose resolvers may resolve harmful domains normally. Security-focused resolvers can block some known threats, but no DNS filtering service catches every phishing site, malware host, or newly registered malicious domain. Continue using appropriate endpoint protection, browser security, software updates, and safe browsing practices.

Some Networks Require Their Own DNS

Workplaces, schools, VPNs, and managed networks may depend on internal DNS names, filtering rules, monitoring, or authentication policies. Replacing those DNS settings with a public resolver can break access to internal resources or bypass approved controls.

Business administrator note: In an Active Directory environment, domain-joined clients generally need to use the organization's internal DNS servers for domain discovery and internal name resolution. If external resolution is required, configure approved forwarders on the internal DNS infrastructure rather than assigning public DNS directly to every client.

DNS Answers Can Differ Between Providers

Websites may use content delivery networks, geographic routing, or different DNS records. Different resolvers can return different valid addresses. A public resolver is not guaranteed to select the fastest content server for every user or application.

Privacy and Security Considerations

Choose a provider deliberately. DNS requests can reveal domains you look up. Review the provider's privacy policy and retention practices.
Use encrypted DNS where appropriate. DoH and DoT protect DNS traffic between the client and resolver when configured correctly.
Understand the limits of encryption. The resolver still processes the queries. Encrypted DNS does not automatically encrypt the website connection, conceal all traffic metadata, or make you anonymous.
Be careful with filtering. Security or family filters may block legitimate websites. Confirm the resolver profile before deploying it to a business or household.
Keep business policies intact. Do not bypass required corporate DNS, logging, security controls, or internal name resolution without authorization.

Troubleshooting Public DNS Problems

Problem	Possible cause	What to try
Websites stop resolving after changing DNS	Incorrect address, network restriction, or resolver connectivity issue	Check the configured addresses and test the original settings. Restore the previous configuration if needed.
Some websites work and others fail	Filtering, cached records, a domain-specific issue, or differing DNS answers	Test the affected domain, compare another trusted resolver, and check whether the provider filters that domain.
DNS works in Command Prompt but not in a browser	The browser may use its own Secure DNS setting, a VPN, a proxy, or another network component	Review browser DNS settings and VPN or security software configuration.
Internal company resources stop working	The device is using a public resolver instead of the required internal DNS	Restore the organization's approved DNS settings and contact the network administrator.
Changing DNS does not improve browsing speed	DNS may not be the bottleneck	Check Wi-Fi quality, latency, packet loss, ISP performance, browser extensions, and the website's own server response.

How to Restore the Previous DNS Settings

If a DNS change causes connectivity problems, return to the same network settings page where the change was made.

Restore the original DNS addresses you recorded before the change, or select the automatic DNS setting if that was the original configuration.
Save the changes and reconnect to the network if necessary.
Run a DNS lookup and test several websites.
If the problem persists, check VPN, proxy, browser Secure DNS, router, and ISP settings.

For router-level changes, restore the original WAN or DHCP DNS values. On a managed business network, contact the administrator before changing or restoring DNS settings.

Frequently Asked Questions

Is public DNS free?

Many public DNS resolvers, including Google Public DNS and Cloudflare's standard resolver, are available free of charge. Some providers also offer paid products or additional services.

Is Google Public DNS better than my ISP's DNS?

It depends on the network. Google Public DNS may improve lookup speed or reliability for some users, while an ISP's resolver may perform equally well or better in a particular location. Test both under similar conditions.

Can public DNS make my internet faster?

It can reduce DNS lookup delays when the chosen resolver performs better, but it does not increase your internet bandwidth. Overall browsing speed may not noticeably change.

Which public DNS is best for security?

If you want DNS-level blocking of known malicious domains, consider a security-focused provider such as Quad9 and review its current filtering policy. DNS filtering is only one security layer and cannot replace endpoint protection or safe browsing practices.

Does public DNS hide my browsing history from my ISP?

No. Encrypted DNS can prevent the ISP from directly reading ordinary DNS queries in transit, but the ISP may still observe destination IP addresses and other traffic metadata. The DNS provider processes the queries, and DNS is not a substitute for a VPN.

Can I use Google Public DNS and Cloudflare DNS together?

You can configure addresses from different providers in some systems, but the system may use either resolver, and their responses or filtering policies may differ. For consistent filtering and troubleshooting, use a single provider's recommended pair unless you have a specific reason to mix providers.

Should I change DNS on my computer or router?

Change it on an individual device when you want to test or configure only that device. Change it on the router when you want compatible devices on the network to receive the setting automatically. Router behavior varies, and some devices or browsers can override the router's DNS choice.

Can public DNS block advertisements?

Some DNS providers offer filtering profiles that block certain advertising and tracking domains. This will not block every advertisement, particularly ads served from the same domains as other website content.

Is public DNS suitable for a company network?

It can be suitable for some business uses, but administrators must consider internal DNS, Active Directory, VPNs, security filtering, logging, and organizational policies. Do not replace required internal DNS servers on domain-joined computers without an approved design.

Conclusion

Public DNS provides an alternative to the DNS resolver supplied by your ISP or network administrator. It can improve DNS lookup performance in some situations and may offer security filtering or encrypted DNS features, depending on the provider.

For general home use, Google Public DNS and Cloudflare DNS are useful starting points for comparison. Quad9 is worth considering when blocking known malicious domains is a priority. Choose based on your measured results, privacy requirements, filtering needs, and compatibility with your network, and keep a record of the original settings so you can revert if necessary.

Sources

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