DNS: guide and lookup
What DNS is, which servers are fastest, and how to change DNS on any device. Plus a free DNS lookup tool.
What is DNS, and does changing it speed up your internet? DNS is the phone book of the internet: it turns a name like realmbps.com into the server's IP address. Switching to 1.1.1.1 (Cloudflare) or 8.8.8.8 (Google) adds no Mbps to your line, but it cuts lookup time, so pages start loading sooner and browsing feels snappier. For file downloads it makes no measurable difference.
DNS lookup tool
Enter a domain to see its DNS records in real time (A, AAAA, MX, TXT, NS…). The lookup uses Google DNS-over-HTTPS.
What is DNS?
DNS (Domain Name System) is the internet's phone book: it translates site names you can remember (e.g. realmbps.com) into the numeric IP address of the server that hosts them. Computers route traffic by IP, but people think in names, and DNS is the layer that bridges the two. Every time you open a site, tap a link, or load an image from another domain, your device fires off a DNS query behind the scenes. By default you use the resolver your ISP assigns, but you're free to switch to a public resolver that is often faster, more reliable and more private.
How DNS resolution works
Turning a name into an address takes a short relay of questions, usually finished in milliseconds. Your device first asks a recursive resolver (your ISP's or a public one). If that resolver doesn't already have the answer cached, it asks a root server which name servers handle the top-level domain, then the TLD server (for example the one responsible for .com) which points it to the domain's authoritative name server, the final source of truth that returns the IP. The resolver caches the result for a period set by the record's TTL (time to live), so the next visitor gets an instant answer without repeating the whole chain. Only after this resolution completes can your browser open the actual connection to the site.
The main DNS record types
A domain's DNS zone holds several kinds of record, each answering a different question. An A record maps a name to an IPv4 address, and an AAAA record maps it to an IPv6 address. A CNAME is an alias that points one name at another name rather than an IP, handy for subdomains that should follow a canonical host. MX records say which mail servers accept email for the domain, with priorities that decide the order. TXT records store arbitrary text and are widely used for email authentication (SPF, DKIM and DMARC) and for proving domain ownership. NS records list the authoritative name servers for the domain itself. You can inspect any of these for a live domain with the lookup tool at the top of this page.
Why change your DNS?
Changing DNS can speed up how quickly sites load when a nearby resolver answers faster than your ISP's, boost your privacy (some resolvers pledge not to log or sell your queries), add optional anti-malware and phishing filtering, and sometimes route around clumsy DNS-level blocks. It won't raise your download Mbps, because DNS only handles the name-to-address lookup, not the transfer of data itself, but it can make browsing feel snappier and steadier, especially on pages that pull content from many domains. Best of all it's free and fully reversible: switch back to Automatic at any time.
The most popular public DNS
| DNS | IPv4 | IPv6 |
|---|---|---|
| Cloudflare | 1.1.1.1 · 1.0.0.1 | 2606:4700:4700::1111 |
| 8.8.8.8 · 8.8.4.4 | 2001:4860:4860::8888 | |
| Quad9 | 9.9.9.9 · 149.112.112.112 | 2620:fe::fe |
| OpenDNS | 208.67.222.222 · 208.67.220.220 | 2620:119:35::35 |
How to change your DNS step by step
- Windows 11 / 10 — Settings → Network & Internet → your adapter (Wi-Fi or Ethernet) → Edit DNS server assignment → Manual → turn on IPv4 → enter your preferred and alternate DNS → Save.
- macOS — System Settings → Network → select your connection → Details → DNS → click + and add the addresses → OK.
- Android — Settings → Network & Internet → Private DNS → Private DNS provider hostname → enter e.g. dns.google or one.one.one.one → Save.
- iPhone / iPad — Settings → Wi-Fi → tap the (i) next to your network → Configure DNS → Manual → add servers → Save.
- Router — Log into your router's panel (usually 192.168.1.1) → Internet/WAN or DHCP section → set the DNS → save. This way it applies to your whole home.
Setting DNS on the router is the tidiest option because every device inherits it automatically, including smart TVs and consoles that have no DNS setting of their own. Setting it per device is useful when you only want to change one machine or override the network default. After switching, reload a page or two to confirm sites still resolve normally.
DNS privacy: encrypted DNS (DoH and DoT)
Classic DNS queries travel in plain text, which means your ISP, and anyone able to watch the network, can see the names of the sites you look up even when the sites themselves use HTTPS. Encrypted DNS closes that gap. DoH (DNS over HTTPS) wraps queries inside ordinary HTTPS traffic so they blend in with normal web requests, and it's the option most browsers can enable directly in their settings. DoT (DNS over TLS) encrypts the same queries over a dedicated secure channel and is typically configured at the operating-system or router level; Android's "Private DNS" feature uses it. Both hide the content of your lookups from onlookers, though the resolver you choose still sees them, so it's worth picking a provider with a clear no-logging policy.
Flush the DNS cache and fix "DNS not responding"
Your device and browser keep a local DNS cache so repeat visits skip the lookup, but a stale entry can send you to an old address after a site moves. Clearing it forces fresh answers. On Windows, open Command Prompt and run ipconfig /flushdns. On macOS, run sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder in Terminal. On Android or iOS, toggling Airplane mode or restarting the device clears it. If you see errors like "DNS server not responding" or "this site can't be reached," try flushing the cache, then switch to a public resolver from the table above, reboot your router, and test whether other sites load. When most sites work but one doesn't, the fault is usually that domain's own DNS rather than yours; when nothing resolves at all, the problem is your resolver or your connection.
FAQ
What are Google's DNS?
8.8.8.8 and 8.8.4.4 (IPv4), 2001:4860:4860::8888 on IPv6. They're free, fast and very widely used.
Does changing DNS increase my internet speed?
It won't raise your download Mbps, but it can make sites open faster and browsing more reliable. Your line speed stays whatever your plan provides.
Google or Cloudflare, which is better?
Both are excellent. Cloudflare (1.1.1.1) leans hard on privacy and speed; Google (8.8.8.8) is rock-solid and ubiquitous. Try them and keep whichever works best.
Is it safe to change DNS?
Yes, as long as you use well-known public DNS (Google, Cloudflare, Quad9). It's a reversible change: you can always switch back to Automatic.
What's the difference between an A record and a CNAME?
An A record points a name directly at an IPv4 address (AAAA does the same for IPv6). A CNAME is an alias: instead of an address it points one name at another name, which then resolves to the address. CNAMEs are handy for subdomains that should always follow a canonical host.
What is DNS over HTTPS (DoH)?
DoH encrypts your DNS queries inside ordinary HTTPS traffic so your ISP and network onlookers can't read which sites you look up. Most modern browsers can turn it on in their settings. DNS over TLS (DoT) does the same over a dedicated secure channel, usually set at the system or router level.
How do I flush my DNS cache?
On Windows, run "ipconfig /flushdns" in Command Prompt. On macOS, run "sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder" in Terminal. On phones, toggling Airplane mode or restarting clears it. Flushing forces fresh lookups when a stale entry sends you to an old address.
Why do I get "DNS server not responding"?
It usually means your resolver can't be reached or is failing. Try flushing your DNS cache, switch to a public resolver such as Cloudflare or Google, and reboot your router. If only one site fails while others load, the issue is that domain's DNS, not yours.
