Have you ever wondered how it's possible to access a website by typing an easy-to-remember name instead of a sequence of numbers? The person who does this translation is... DNS — the Domain Name System. It's one of the most invisible parts of the internet and, at the same time, one of the few you can change in two minutes, for free, and feel the difference.
This guide explains what DNS does, what changing servers changes, and—equally important— what doesn't change, Because there's a lot of misinformation circulating out there. Then come the best-known public service providers with their addresses, what each one promises in terms of privacy, the step-by-step process for switching on Android and iPhone, the Brazilian perspective on the issue, and the cases where the best decision is precisely... no to replace.
What is DNS in practice?
Computers don't communicate by names, but by numerical addresses. When you type a website address, your device asks a... recursive DNS server What is the number corresponding to that name? This server looks for the answer, returns it, and only then does the connection begin. It's such a quick step that nobody notices—but it happens dozens of times on each page, because a modern page loads content from many different domains.
By default, this task is performed by your internet service provider's server, which is automatically configured when you connect. Changing DNS simply means choosing a different provider for this query. Nothing more than that—which is why the change is reversible and low-risk.
What changes when switching DNS servers — and what doesn't — changes.
It doesn't change. The speed of your connection. If you have 100 Mbps, you will continue to have 100 Mbps. DNS does not transport the website content: it only answers the initial query. No DNS server increases your contracted bandwidth, and anyone promising "faster internet" by changing your DNS is considerably exaggerating.
Change Resolution time—the milliseconds between the question and the answer. Because this step is repeated many times per page, a fast resolver gives the feeling of websites "loading faster," especially on the first access to each domain. It's a real and modest gain, measured in milliseconds, not megabits.
It also changes. Who knows which websites you visit if you distrust the default resolver; which domains are blocked, in the case of servers with filtering; and the reliability when the provider's DNS is unstable — a classic symptom of "the internet is working, but the websites won't load".
It could get worse. One thing, and almost no one mentions it: choosing the content server closest to you. This is explained in the section about Brazil, further down, and is the main reason why some people feel that things "got worse" after switching.
Known public DNS servers
Cloudflare
Addresses: 1.1.1.1 and 1.0.0.1. Encrypted DNS name: one.one.one.one
It is usually the fastest for most measurements and is the easiest to remember. The company claims not to store the address of the person consulting the file on disk and to delete operational records within a short period, with external audits published. There are two variants with filters: 1.1.1.2, which blocks malicious domains, and 1.1.1.3, which also blocks adult content — useful as a light parental control.
Google Public DNS
Addresses: 8.8.8.8 and 8.8.4.4. Encrypted DNS name: dns.google
It is the oldest and most widely used public server in the world, with enormous infrastructure and stability that is difficult to surpass. The company states that it maintains temporary records for short periods and permanent records in anonymized form, without linking the query to your account. It does not filter content: it responds with what exists.
Quad9
Addresses: 9.9.9.9 and 149.112.112.112. Encrypted DNS name: dns.quad9.net
Operated by a non-profit foundation based in Switzerland, its central purpose is to block domains associated with scams and malicious programs, using threat intelligence lists. It claims not to collect data that identifies the user. It's an option for those who want a layer of security without installing anything.
OpenDNS
Addresses: 208.67.222.222 and 208.67.220.220
Cisco's service, a veteran in the category, is known for its category-based filtering options via registration. There is a variant ready for home use, the FamilyShield (208.67.222.123 and 208.67.220.123), which blocks adult content without any configuration. It is the typical choice for those who want filtering on their home router.
AdGuard DNS
Addresses: 94.140.14.14 and 94.140.15.15. Encrypted DNS name: dns.adguard-dns.com
It blocks advertising and tracking domains at the resolution level, which also works within applications, not just in the browser. The side effect is well-known: sometimes a website or app breaks because it depends on a blocked domain. It's worth knowing this before you start testing—and remember that free websites, including this one, are supported by advertising.
Encrypted DNS: What are DoH and DoT?
There's a detail that surprises many people: even when browsing websites with a padlock icon, the traditional DNS lookup travels open. Whoever is in the way—the provider, the owner of the public Wi-Fi—doesn't see the content of the pages, but they do see the list of domains you requested. The padlock protects what you do on the site; it doesn't protect the question that opened the site.
It was to solve this that the DNS over HTTPS (DoH) and the DNS over TLS (DoT). The two encrypt the query between your device and the chosen resolver. On Android, the feature appears as Private DNS and uses DoT — that's why he asks for one. name It's a server number, not a number.
Is it worth it? On a public network, yes, without a doubt. At home, it's a matter of trust: you stop showing your queries to the provider and start showing them to the resolver operator. It's not absolute privacy — it's choosing who to trust.
How to change the DNS on Android
- Open Settings > Network and internet (on some devices, Connections).
- Search Private DNS. It may be found under "More connection settings".
- Choice Private DNS provider hostname.
- Enter the name of the chosen service:
one.one.one.one,dns.google,dns.quad9.netordns.adguard-dns.com. - Save and test by opening some websites.
The big advantage of this approach: private DNS is useful for Wi-Fi and mobile data at the same time, The query will be encrypted. To undo, return to the same screen and choose "Automatic". If a specific Wi-Fi network stops working after the change—the typical case being a public network login portal—simply turn it off temporarily.
How to change the DNS on an iPhone
- Open Settings > Wi-Fi.
- Tap the information icon (i) next to the connected network.
- Go to Configure DNS and choose Manual.
- Remove the existing servers and add the desired addresses, such as 1.1.1.1 and 1.0.0.1.
- Tap on Save.
Two important observations. First: this configuration is valid. only for that Wi-Fi network — On another network, this needs to be repeated. Second: to also work on mobile data and in encrypted form, the iPhone requires a configuration profile or the official application of the DNS service itself, which installs this profile automatically. Install profiles only from trusted sources: they control all name resolution on the device.
Replacing it on the router is more worthwhile.
If the goal is to make it work for the entire house—television, console, computers, visitors—the right place to find it is the router. The path varies by model, but it's usually found under "WAN," "Internet," or "LAN/DHCP," in a field for primary and secondary DNS servers. Once the change is made, all devices will use the new server without individual configuration.
Two things to note: some routers provided by ISPs don't allow you to change this setting; and the filter you configure there, such as adult content, only applies within your network — on 4G, the phone reverts to using the carrier's DNS. Write down the old configuration before changing anything.
The Brazilian perspective: when it's not worth switching
Here's the part that's missing from almost every text on the subject. Large video, gaming, and social media platforms maintain caching servers within Brazilian operators And at the country's traffic exchange points — the one in São Paulo is one of the largest in the world. This means that the video you watch often doesn't come from abroad: it comes from a server a few kilometers away from you, within your provider's own network.
The DNS response determines which of these servers you will be sent to. Some public resolvers send a portion of your network address so that the platform can choose the closest server; others do not send it, due to privacy policies—and in that case, the platform may choose with less precision. The practical result: in some provider and service combinations, Changing the DNS worsens video and download speeds., even if name resolution becomes faster.
Other cases where it's better to stick to the standard:
- Corporate, school, or university network. Internal names only exist in the network's own DNS. Changing them breaks access to internal systems.
- Wi-Fi with login screen. Airport, hotel, café: the portal depends on the local DNS to appear.
- Filter content at home. If you've set up parental controls on your router via DNS, letting your child change the DNS on their phone bypasses the filter — and it's good to know that this is one of the most common ways to circumvent it.
- VPN enabled. VPNs typically enforce their own DNS; configuring a different one on top of that can lead to conflicts and sometimes query leaks.
- Everything is working fine. If pages load quickly and nothing freezes, the improvement will be imperceptible.
It's also worth clarifying a common practice here: in Brazil, website blocking ordered by court order is carried out by internet service providers, and changing DNS sometimes bypasses this block. Bypassing it doesn't legalize what the court order blocked—the responsibility for access remains with the user.
How do I know if it was worth it?
- Compare the before and after photos taken at the same location and time. A test done on home Wi-Fi and compared to another done on 4G proves nothing.
- Measure what you use. Open the five websites you visit most often, with your browser cache cleared, and see if the difference is noticeable.
- Test the download speed, not just the browsing speed. This is where the effect of choosing a content server comes into play.
- Wait a week before deciding. The initial impression of speed in the first minute is deceiving.
- Note the old configuration. To return without a headache. In almost all cases, "Automatic" solves the problem.
How to change DNS in Windows and macOS
The article has already covered cell phones and routers, but those who spend the day on their computers get the same benefit with two minutes of setup — and the change only applies to that machine, making it great for testing before messing with the entire network.
On Windows, In current versions, the path is: Settings, Network & Internet, tap on the connection in use (Wi-Fi or Ethernet), find the DNS server assignment and choose edit. Change from Automatic to Manual, enable IPv4 and fill in the preferred and alternate servers. In the latest versions there is also a DNS encryption field, which enables encrypted queries when the chosen server offers support.
On macOS, Open System Settings, go to Network, select the active connection, go to Details, and then to the DNS tab. Use the plus button to add the desired addresses and remove those from your provider. Confirm and apply.
In both systems, make a note beforehand of the settings. Generally, you can simply revert to Automatic to undo them, but on a work machine, there might be an internal server configuration noted there that you won't remember later.
When the problem isn't DNS: a three-minute diagnosis.
Replacing the server has become the first recipe for any slowdown, and most of the time the culprit is something else. This sequence distinguishes one case from the other without installing anything:
- Is it just one website or are they all included? If only one address doesn't open and the rest work, the problem is with the website, not its name resolution.
- Does it work on mobile data? Turn off Wi-Fi on your phone and test. If it opens using mobile data, the problem is with your local network or your internet provider.
- Does another device on the same network have the same symptom? If only one device fails, it's not the home DNS system—it's that particular device.
- Clear the name cache. The system stores old responses for a while. In Windows, the DNS cache clear command resolves this; macOS has an equivalent. Restarting the device has a similar effect.
- Restart your router. Unplugging the device for thirty seconds fixes an embarrassing number of home network problems.
- Try a second browser. Extensions, blockers, and secure DNS settings within the browser itself cause symptoms identical to those of a faulty resolver.
If, after all this, the speed remains slow on all devices and websites, the problem is likely with your internet connection—and no name server will solve that.
Smart TVs, consoles, and devices that don't let you choose.
Televisions, video game consoles, streaming devices, and voice assistants also rely on name resolution, and almost none offer a decent screen for configuring this. Some allow you to manually enter the primary and secondary servers along with the address and mask during network setup—which forces you to manually assign a fixed address to the device and complicates things.
For these cases, the practical solution is the router: once configured there, the new server applies to everyone who connects, without the need for an individual configuration screen. However, a specific warning is in order: streaming and gaming devices are precisely those that benefit most from the caching servers within Brazilian internet providers. If, after the change, the video starts to freeze or game update downloads become slower, this is the first suspect—and switching back to the provider's server only for these devices is usually the best approach.
There are also those who ignore the configuration: some devices come with fixed servers pre-installed and simply don't use what the router indicates. This isn't a configuration defect, it's a manufacturer's decision.
Questions that arise after the exchange
I switched servers and nothing changed. Is it working?
Older responses are cached for a period of time defined by each domain, so the change isn't instantaneous. Restarting the device speeds things up. It's also worth checking if the browser isn't using its own secure DNS configuration, which bypasses the system's.
Can I use servers from different companies as primary and secondary servers?
It's possible, but the system doesn't predictably switch between the two, and you end up not knowing which one responded. If you intend to have specific filters or privacy, use the pair of addresses from the same service.
I turned on private DNS and the work Wi-Fi stopped working.
Corporate networks often rely on the internal resolver for names that only exist within the network, and some block encrypted queries from the outside. In these cases, it's best to leave it on automatic while connected to that network.
Is a paid DNS server worth it?
It only makes sense when you want what the free version doesn't offer: customized blocklists, a log of your network's queries, and rules per profile. For speed and basic privacy, the well-known free options deliver the same.
Read also
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- Full Memory on Your Cell Phone: A Step-by-Step Guide to Freeing Up Space on Android and iPhone
- Watching Free TV on Your Cell Phone: The Legal and the Risky Options
Common questions
Does changing the DNS increase internet speed?
No. The contracted bandwidth remains the same. What changes is the name resolution time, measured in milliseconds, which gives the impression of pages loading faster on the first access to each domain. In some cases, the change even worsens the choice of the nearest content server.
Is it safe to use a public DNS server?
Yes, use the major, well-known services. Be careful with addresses found in forums and random lists: a malicious resolver can return the wrong address to a legitimate site and lead you to a fake page. Only use established services with a published policy.
Which DNS server is the fastest?
It depends on where you are and which provider you use—there's no universal answer. The honest way to find out is to test two or three on your own connection, at the same time, and compare them.
Does DNS hide my browsing history from my ISP?
Only if it's encrypted (DoH or DoT), and even then only partially: the provider stops seeing the queries, but continues to see the network addresses you connect to. DNS is not a VPN and does not anonymize browsing.
How do I undo this if there's a problem?
On Android, set private DNS to “Automatic”. On iPhone, set DNS to “Automatic”. On your router, restore the noted values or leave them blank to use your provider's values. The change is completely reversible.
Do I need a different DNS server for Wi-Fi and mobile data?
On Android, no: private DNS applies to both connections. On iPhone, manual configuration only works over Wi-Fi networks — to include mobile data, you need a configuration profile or the official app of the chosen service.
Does DNS block ads and viruses?
Some servers block known advertising, tracking, or fraud domains, and this also works within applications. It doesn't replace antivirus software or common sense: a new domain, not yet listed, usually gets through normally.
Conclusion
Switching DNS servers is one of the simplest and most reversible adjustments available, and it can deliver three concrete things: slightly faster name resolution, a layer of protection against malicious domains, and more privacy regarding your provider if you use encrypted DNS. What it doesn't deliver is increased connection speed—and it's good to be aware of that.
If you want a ready-made solution: on Android, enable private DNS with the name of your chosen service, which will encrypt everything and work for both Wi-Fi and mobile data. Prefer security above all else? Go with Quad9. Want the fastest in most measurements? Cloudflare. Want maximum stability? Google. Want a filter for your home? OpenDNS FamilyShield or the 1.1.1.3 variant, directly on your router.
And if, after a week, the videos start buffering more than before, you already know why: it's a problem with the caching servers within the Brazilian internet providers. In this scenario, switching back to "Automatic" isn't a defeat—it's the right choice.
