What is a DNS server? [+ what to do when it isn’t responding]

The internet has a secret identity problem. You type google.com, but your computer can only talk in
numbers (IP addresses). A DNS server is the translator that turns friendly website names into the
numeric addresses machines use to actually connect. In other words: DNS is the internet’s GPS, phone book, and
“wait, which house is this?” friendall rolled into one.

And when it breaks? You get the dreaded message: “DNS server isn’t responding.” Your Wi-Fi looks fine. Your
coffee is still hot. Yet the web refuses to load like it’s on a silent retreat. Don’t panic. By the end of this guide,
you’ll understand what DNS does, why it fails, and exactly how to fix itwithout sacrificing a laptop to the router gods.

DNS server, DNS resolver, and the Domain Name System (DNS): what’s the difference?

People say “DNS server” to mean a few related things, so let’s un-knot the vocabulary:

• DNS (Domain Name System): The global system that maps domain names (like example.com) to IP
  addresses (like 93.184.216.34).
• DNS resolver (usually “recursive resolver”): The service your device talks to first. It hunts down
  the answer by querying other DNS servers if needed, then returns the result to you.
• Authoritative DNS server: The source of truth for a domain. It holds the official DNS records
  (A/AAAA, CNAME, MX, TXT, etc.) that say where services live.

When your laptop says it’s using a “DNS server” like 8.8.8.8 or 1.1.1.1, it’s
typically pointing at a recursive DNS resolver that does the heavy lifting for you.

How a DNS lookup works (without turning into a networking textbook)

Here’s what happens when you visit a website:

1. You ask: Your browser requests the IP address for www.example.com.
2. Your device checks locally: Browser cache, OS cachebasically, “Do I already know this?”
3. Your recursive resolver searches: If it doesn’t have the answer cached, it follows DNS’s hierarchy:
   starting at the root, then the TLD (like .com), then the domain’s
   authoritative server.
4. You connect: With the IP address in hand, your browser can finally talk to the website.

The DNS hierarchy is a big reason the internet scales. Root servers don’t store every website’s IP address; they help
route resolvers to the right place, like the world’s most efficient receptionist.

Why DNS feels instant: caching and TTL

DNS would be painfully slow if every lookup required a full scavenger hunt. That’s why DNS uses
caching. Your device, your router, and your resolver may keep answers temporarily so repeat visits are
fast.

How long does an answer stay cached? That’s controlled by TTL (Time To Live). A record’s TTL tells
caches, “Keep this answer for X seconds, then ask again.” Lower TTLs let changes propagate faster, higher TTLs reduce
DNS traffic and speed things up for stable services.

What exactly is a DNS server responsible for?

A DNS server (again, usually the resolver you configured) is responsible for:

• Resolving names to IP addresses so websites load
• Returning other DNS records (MX for email, TXT for verification/security, SRV for services, etc.)
• Caching answers to reduce latency and improve reliability
• Handling errors like “domain doesn’t exist” (often cached briefly too)

Your DNS choice can affect speed, privacy, and reliability. Many people use their ISP’s DNS by default, but public DNS
resolvers are popular for performance and security features.

Why you’re seeing “DNS server isn’t responding”

That message is basically your computer saying: “I tried to translate the website name into an IP address, and the
translator didn’t answer.” Common causes include:

1) The resolver is down (or timing out)

Your configured DNS resolver might be overloaded, unreachable, or temporarily failing. This can happen with ISP DNS,
public resolvers, or even your router acting as a forwarder.

2) Your router or modem is having a bad day

Home networking gear can get stuck in weird statesespecially after a power flicker, firmware bug, or weeks of uptime.
If multiple devices on your network can’t resolve names, the router is a prime suspect.

3) Your device has stale (or corrupted) DNS cache

If your device cached an outdated answeror cached a “this domain doesn’t exist” responseyou can end up stuck until the
cache expires. Flushing the DNS cache forces a fresh lookup.

4) VPNs, proxies, security software, or “helpful” browser settings

VPN clients and security tools sometimes hijack DNS settings (on purpose) and can misbehave (by accident). Some browsers
also use encrypted DNS features that change where your queries go.

5) The website’s DNS is misconfigured

Sometimes the problem isn’t youit’s them. A domain might have broken records, expired DNS hosting, or propagation issues
after a change.

The fastest way to diagnose DNS vs. “the whole internet is down”

Before you start flipping settings like a game show contestant, do two quick checks:

Check A: Can you reach the internet by IP address?

Try visiting a site by IP (not always reliable due to HTTPS hosting), or do a quick ping test. If your device can reach
a public IP but not domain names, that strongly points to DNS.

Check B: Does it fail on one device or all devices?

• Only one device: likely a device configuration/cache issue.
• All devices: likely router/ISP/DNS resolver issue.

What to do when your DNS server isn’t responding (step-by-step fixes)

Step 1: Do the classic power cycle (yes, really)

Restart your computer and power-cycle your modem/router:

1. Unplug modem/router power.
2. Wait 10–30 seconds (enough time for the gremlins to pack their bags).
3. Plug back in, wait until the lights stabilize.
4. Try loading a website again.

Step 2: Switch to a reliable public DNS resolver

If your ISP DNS is flaky, switching to a public resolver often fixes things immediately. Popular options:

• Google Public DNS: 8.8.8.8 and 8.8.4.4
• Cloudflare: 1.1.1.1 and 1.0.0.1

You can change DNS on your device (affects only that device) or on your router
(affects everything on your Wi-Fi). Router-level is cleaner if the whole household is suffering.

Step 3: Flush your DNS cache

Clearing the DNS cache removes stale records and forces fresh lookups.

Windows

If you’re still stuck, a network stack reset can help (especially after VPN shenanigans):

macOS

Commands vary by version, but a common approach on modern macOS versions is:

Step 4: Turn off VPN/proxy temporarily

Disable VPN and proxy settings, then test again. If DNS works immediately, your VPN app may be assigning a broken DNS
server or blocking resolution.

Step 5: Temporarily disable security software (carefully)

Some antivirus and “web protection” tools filter DNS or inject their own resolver. Briefly disabling them can confirm
whether they’re the culprit. If that fixes it, look for DNS, web shield, or network filtering settings and adjust rather
than leaving protection off.

Step 6: Update router firmware

Router firmware updates can fix DNS forwarding bugs, stability problems, and security issues. Check your router vendor’s
admin panel for updates. If your router is older than your favorite hoodie, consider replacing itnetwork gear has
feelings, and they are “tired.”

Step 7: Use diagnostic tools (when you want receipts)

On Windows, macOS, and Linux, nslookup can tell you whether your resolver is answering:

If you see timeouts, “server can’t be reached,” or repeated failures, you likely have a resolver/connectivity issue.
If it works for some domains but not others, the website’s DNS may be the problem.

Advanced fixes (when the easy stuff didn’t work)

Reset TCP/IP settings (Windows)

If your network stack is corrupted or misconfigured, a reset can help:

Check your hosts file (rare, but spicy)

A modified hosts file can override DNS and send a domain to the wrong IP (or nowhere). This is uncommon unless you’ve
installed certain tools or had malware issues. If a single domain is failing in a weird way, it’s worth checking.

Try a different network

Use a phone hotspot or another Wi-Fi network. If everything works elsewhere, your home network, ISP DNS, or router is
the likely problemcongrats, you’ve narrowed it down without arguing with strangers on the internet (yet).

DNS and security: why your resolver choice matters

DNS over HTTPS (DoH) and DNS over TLS (DoT)

Traditional DNS queries are often unencrypted, which can expose which domains you’re looking up to network observers.
DNS over HTTPS (DoH) encrypts DNS queries by sending them inside HTTPS traffic (often over port 443).
DNS over TLS (DoT) encrypts DNS using TLS directly (commonly over port 853).

Encryption can improve privacy and reduce some forms of manipulationbut it can also complicate troubleshooting in
managed networks where DNS filtering is used for security or parental controls. The takeaway: encrypted DNS is powerful,
but you should understand who you’re trusting as your resolver.

DNS hijacking (why “just DNS” can be a big deal)

If attackers can manipulate DNSat a device, router, ISP, or domain levelthey can redirect users to malicious sites
without touching the real website. That’s why organizations lock down DNS changes, use strong account security at domain
registrars, and monitor DNS records like hawks with caffeine.

FAQ: quick answers people actually search for

Is a DNS server the same as my router?

Sometimes your router forwards DNS requests to a resolver (ISP or public). Some routers also cache DNS. But the actual
“DNS server” you’re configured to use is usually a resolver somewhere else.

Will changing DNS speed up my internet?

It can speed up name lookups, which can make websites start loading faster. It won’t increase your raw download
bandwidth, but it can reduce the “why is this page still thinking?” delay.

Why does DNS work on my phone but not my laptop?

Different devices can use different DNS settings (manual vs automatic), different caches, VPN profiles, or DNS-over-HTTPS
browser settings. That mismatch is a strong clue the issue is local to the laptop.

Bonus: real-world DNS “experiences” (the kind you’ll recognize instantly)

DNS problems rarely announce themselves politely. They show up disguised as “Wi-Fi issues,” “browser bugs,” or that
ominous feeling that your computer is judging you. Here are a few common real-world scenarios and what typically fixes
themso you can skip the drama and go straight to the solution.

Experience #1: “Only ONE website won’t load. Everything else is fine.”

This is classic “website-side DNS” or “cached weirdness.” If bank.example.com fails but everything else works,
try these in order: (1) open it on your phone using cellular data, (2) run nslookup for that domain, (3)
flush DNS cache, and (4) switch resolvers temporarily (Google/Cloudflare) to see if the issue is isolated to your ISP’s
resolver. If switching DNS fixes it, your ISP resolver may be caching a stale answer or struggling with that domain.

Experience #2: “Nothing loads… but Netflix on the TV still works somehow.”

Streaming apps can keep working because they already resolved the service earlier and are happily using cached IPs.
Meanwhile, your laptop is trying to resolve new domains and failing. That’s why DNS issues can feel “selective” and
confusing. The fix is usually a router reboot, followed by switching router DNS to a stable public resolver if the issue
keeps returning.

Experience #3: “It started right after I installed a VPN.”

VPNs often push their own DNS settings to prevent leaks, which is gooduntil it isn’t. A misconfigured VPN can route DNS
requests to a resolver that times out, blocks certain domains, or breaks when you switch networks. Quick test: disconnect
the VPN and try again. If DNS instantly works, look for the VPN’s “DNS” or “secure DNS” settings, update the VPN client,
or choose a different DNS mode.

Experience #4: “Office network works. Home network doesn’t. Same laptop.”

That usually means your home router/ISP DNS is the weak link. Home routers sometimes forward DNS poorly when under load,
after firmware issues, or when their “DNS proxy” feature gets stuck. Switching DNS at the router level often fixes it for
every device at once. If it keeps happening weekly, it’s also a hint that firmware updates (or a newer router) will save
your future self from yelling at blinking lights.

Experience #5: “After changing DNS, some sites load the old version for hours.”

Welcome to TTL and caching. Even after you update DNS records for a domain (say you moved a site to a new host), caches
around the internet may keep the old answer until the TTL expires. That’s normal. The practical lesson: when planning DNS
changes for a website, reduce TTL ahead of time (hours or a day before) so changes propagate fasterthen raise it again
once everything is stable.

Experience #6: “My smart home devices keep dropping, and DNS looks suspicious.”

IoT devices are tiny computers with tiny patience. If DNS resolution is slow or inconsistent, devices may “fail closed”
and appear offline. Router DNS changes can help, but also check for router features like DNS filtering, parental controls,
or security scanning that might block the device’s cloud endpoints. When in doubt, try a known-stable public DNS and see
if the device becomes magically well-behaved again.

Conclusion

A DNS server is the internet’s translator: it converts domain names into IP addresses so your browser
can connect. When DNS isn’t responding, the fix is usually straightforwardrestart your network gear, switch to a
reliable public resolver, flush DNS cache, and remove anything interfering (VPNs, proxies, security filters). Once you
know the pattern, DNS errors stop being spooky and start being… mildly annoying. Which is the best kind of annoying.