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If you are wondering how to fix slow DNS lookup, first confirm that name resolution is causing the delay. Test several domains, compare your current resolver with another trusted DNS service, and check whether the problem affects one device or your whole network. Clear a stale local cache when appropriate, then change DNS settings only if testing shows a reliable improvement.
A website that pauses before anything appears can feel like a slow internet connection. Sometimes DNS is responsible; sometimes the delay happens later, while connecting to the server or waiting for its response. This guide helps you tell the difference and choose a fix without changing settings unnecessarily.
If you need to identify your device or gateway before troubleshooting, follow our guide to finding your IP address on Windows, Mac and phones. The local address and the public address shown by websites serve different purposes.
What is a DNS lookup and why can it be slow?
DNS translates a domain name into an IP address that your device can use to reach a service. Your computer, browser and DNS resolver may cache answers, avoiding the need to repeat every lookup from scratch.
A delay can occur when a configured resolver responds slowly, packets are lost, or a router struggles to forward requests. A particular website may also have problems with its authoritative nameservers, which supply its DNS records. These are different failure points, so one fix will not suit every situation.
The useful distinction is where the waiting happens. If opening a new website takes several seconds but an existing download continues normally, DNS is worth investigating. That observation is a clue, however, rather than proof.
How can you confirm that DNS is causing the delay?
Start with three comparisons: another website, another browser and another device. Then try the affected device on a different connection, such as a trusted mobile hotspot, if available.
Write down what changes. If every device struggles only on your home network, investigate the router, connection or configured resolver. If one browser struggles while others work, examine that browser's settings. If just one domain fails across different networks, the website itself deserves closer attention.
Avoid opening a website's IP address as your main diagnostic test. HTTPS certificates, shared hosting and routing can make that fail even when DNS is working correctly.
For an actual lookup check, open Command Prompt on Windows or Terminal where available and run:
nslookup example.comThen compare explicit resolvers:
nslookup example.com 1.1.1.1
nslookup example.com 8.8.8.8These commands query your default resolver, Cloudflare and Google respectively. Use several public domains, including the affected one. A successful response shows that the tested query received an answer; it does not prove the entire connection is healthy. Microsoft documents nslookup as a DNS diagnostic tool. [1]
How should you run a DNS speed test?
A useful DNS speed test measures resolution rather than download bandwidth. The Mbps number from a normal internet speed test cannot tell you how quickly a particular name resolves.
On macOS, or Linux with dig installed, try:
dig example.com
dig @1.1.1.1 example.com
dig @8.8.8.8 example.comLook for the query time and response status. Run the tests several times against a small selection of domains. The first query may require more work than subsequent queries because the resolver can reuse cached information. Compare first responses and repeated responses separately. ISC provides the dig tool and its documentation. [2]
For website timing on macOS or Linux, curl can provide another useful view:
curl -o /dev/null -sS -w 'DNS: %{time_namelookup}s\nTotal: %{time_total}s\n' https://example.com/In Windows Command Prompt, use:
curl.exe -o NUL -sS -w "DNS: %{time_namelookup}s\nTotal: %{time_total}s\n" https://example.com/Run each command directly in the indicated shell. In a Windows batch file, percent signs need different escaping. The DNS field reports curl's name-resolution timing, while Total includes the request's other stages. Proxies and caches can affect interpretation. [3]
Suppose a hypothetical test reports 0.020 seconds for DNS and 2.5 seconds overall. Most of that request's delay lies elsewhere. If DNS alone repeatedly takes 1.5 seconds across unrelated domains, investigate the resolver or network path. These examples illustrate interpretation; they are not measurements from your connection or universal performance thresholds.
What should a DNS benchmark compare?
A DNS benchmark should compare consistency as well as speed. Record the resolver, domain, approximate response time and whether the query succeeded. Repeat the same small test set at another time before making a permanent change.
Consider this practical checklist:
- Does the resolver answer reliably across different domains?
- Are occasional timeouts hiding behind a good average?
- Are you comparing similar cached and uncached conditions?
- Does the service provide the filtering or privacy settings you need?
- Does normal browsing improve after the change?
Do not pick a provider from a single winning result. Network conditions vary, and a resolver that performs well elsewhere may not perform best on your connection. A browser-based testing site can also measure a different path from your device's normal DNS requests, so check its methodology.
When should you flush DNS cache?
Flush DNS cache when your device appears to be holding an outdated or unsuccessful lookup, especially after a DNS change or when other devices can reach a site normally.
The phrases "flush DNS cache" and "clear DNS cache" describe the same basic troubleshooting action. On Windows, open Command Prompt as administrator and run:
ipconfig /flushdnsWindows should confirm that the DNS resolver cache was flushed. Close and reopen the affected application, then test again. Microsoft's ipconfig documentation explains that this clears the local resolver cache, including dynamically added negative entries. [4]
On Linux systems that use systemd-resolved, the corresponding command is:
sudo resolvectl flush-cachesThis is not a universal Linux command: distributions can use different resolvers. Check your system's configuration before following distribution-specific instructions. The systemd documentation describes the supported cache operation. [5]
For macOS, restart the Mac as a straightforward first step if you are unsure which cache-reset instructions apply to your version. Avoid copying an old Terminal command without checking compatibility.
Cache clearing is a diagnostic step, not routine speed maintenance. It does not clear your ISP's resolver cache or a website's DNS records, and the next lookup may take longer because the local answer must be obtained again.
How do you change DNS server settings safely?
Change DNS server settings when repeated comparisons suggest that your current resolver is unreliable or noticeably slower. Save your existing configuration first so you can reverse the change.
Two public IPv4 resolver pairs are:
Use the matching pair for the service you are testing. Keep IP addressing automatic unless your network specifically requires a static address. Changing DNS does not require inventing a new IP address, subnet mask or gateway.
On Windows, a practical route is:
- Press Windows + R, enter
ncpa.cpl, and open your network connections. - Right-click the active Wi-Fi or Ethernet adapter and choose Properties.
- Select Internet Protocol Version 4 (TCP/IPv4), then Properties.
- Keep the existing IP configuration unchanged.
- Select the option to use specified DNS server addresses and enter your chosen pair.
- Save, reconnect if necessary, and repeat your tests.
Google's setup guide documents configuring resolvers through the adapter's TCP/IP properties. Labels and available controls can vary by Windows version and device policy. [6]
On a Mac, open System Settings, select Network, choose the active service, then open Details and DNS. Record the current entries before adding your selected servers and applying the change. Apple documents this settings path. [8]
IPv6 DNS settings can remain active independently of IPv4. Follow your provider's instructions if your network uses IPv6; do not disable IPv6 simply to force a test result.
On work or school networks, ask the administrator before changing resolvers. Internal names, VPN access and filtering may depend on the organization's DNS. If browsing breaks, restore the recorded settings or the original automatic DNS configuration.
What does DNS server not responding actually mean?
A "DNS server not responding" message means that the relevant lookup did not receive the expected response through the current configuration. It does not identify a single cause by itself.
First check whether the device has a working network connection. If it has no connectivity, choosing another resolver may accomplish nothing. If the connection works, compare the default resolver with an explicit query to another permitted resolver.
When the default fails but another answers consistently, investigate the configured DNS service or router forwarding. When all tested resolvers fail, the network may be blocking direct DNS queries, the connection may be broken, or a VPN or security product may be influencing traffic. Google provides a troubleshooting process for separating resolver, network and domain problems. [9]
Do not disable your firewall or antivirus as a blanket fix. Review relevant settings or contact support with the test results. On managed networks, failed public-resolver tests may reflect intentional policy rather than a fault. Our guide to cybersecurity basics explains broader steps for protecting your devices and connections.
Can your router or Wi-Fi connection cause DNS delays?
Yes. A weak or congested connection can delay or lose DNS requests along with other traffic. Testing over Ethernet, where practical, helps separate wireless conditions from resolver performance.
Restart your router normally, following its manufacturer's instructions, and allow it to reconnect. Restarting is different from a factory reset; avoid the reset button unless you intend to erase the configuration.
If several devices show the same symptoms, check for router firmware updates through the manufacturer's supported interface. Before changing router-wide DNS settings, test the proposed resolver on one device. That keeps the comparison manageable and makes reversal easier. For related router protection steps, see our guide to securing home WiFi.
If the issue persists, give your ISP concrete evidence: affected times, tested domains, whether Ethernet behaves differently, and whether an alternate resolver changes the result. "Websites pause before loading" plus repeatable results is more useful than a general report of slow internet.
Why is DNS slow in Chrome but normal elsewhere?
Browsers can use different DNS paths. Chrome's Secure DNS setting may send lookups to a selected encrypted DNS provider instead of following the same path as your command-line tests.
Open Chrome Settings, then Privacy and security, Security, and review Use secure DNS. Check whether a custom provider is selected. Compare with the current provider option or another trusted, supported configuration, then restore your preferred secure setup after testing. Availability can depend on device management and other settings. Google's Chrome help explains Secure DNS behavior. [10]
Also test a clean browser profile or review extensions if the issue stays confined to Chrome. Avoid treating old internal browser URLs as permanent instructions; settings change between releases.
If a VPN is involved, compare normal behavior with the provider's recommended troubleshooting configuration. Do not override its DNS blindly, because private resources or leak protection may depend on it.
What if only one website has slow DNS lookup?
If unrelated websites resolve normally, stop making broad changes to your device. Test the affected domain through multiple resolvers and, if possible, another network.
A website owner may need to investigate authoritative nameserver availability, delegation, DNSSEC validation or a problematic record chain. Google's domain troubleshooting guide covers failures originating from a domain's DNS configuration. [11]
As a visitor, report the domain, time and observed errors to the owner. As the owner, compare DNS timing with connection and server-response timing before changing hosting or caching plugins. Cloudflare's slow-website guide treats these as separate parts of performance diagnosis. [12]
A faster resolver cannot repair a broken authoritative configuration. Likewise, changing your computer's resolver cannot fix a slow application server after resolution has already completed.
How do you know the fix worked?
Repeat your original tests under similar conditions. Check the same domains, use the same connection and compare both the first lookup and subsequent requests. Then try everyday browsing rather than relying entirely on a benchmark number.
Keep a short before-and-after record. Change one setting at a time so you can identify what helped. If the improvement disappears or a service stops working, revert the last change and investigate the next likely cause.
The goal is reliable browsing with fewer unexplained pauses. Once lookups respond consistently and the remaining delay occurs elsewhere, move on to that part of the connection instead of repeatedly flushing caches.
Frequently asked questions
Will changing DNS make downloads faster?
It may reduce the wait before a connection begins, but it does not increase your broadband plan's bandwidth. DNS can also influence which service endpoint is returned, so real results vary. Measure browsing and download behavior separately.
How often should I clear DNS cache?
Use it when troubleshooting a specific problem, not on a daily schedule. Healthy caches reduce repeated work. Clearing them repeatedly can remove useful answers without addressing the underlying fault.
Is Google DNS faster than Cloudflare DNS?
Neither is guaranteed to be faster on every connection. Compare response time, reliability and the features you need on your own network before choosing.
Does changing DNS affect every device?
A change on one computer generally applies to that computer's configured connection. A router change may affect devices that obtain DNS settings from it, while manually configured devices, browsers or VPNs may behave differently.
What should I try first?
Compare another website and another device, then run a lookup test. Those simple checks narrow the problem before you clear caches, change resolvers or adjust network settings.
Sources and further reading
- Microsoft Learn – nslookup
- ISC – dig and delv
- curl manual – write-out timing variables
- Microsoft Learn – ipconfig
- systemd – resolvectl
- Google Public DNS – configuration
- Cloudflare – resolver IP addresses
- Apple Support – DNS settings on Mac
- Google Public DNS – troubleshooting
- Google Chrome Help – Secure DNS
- Google Public DNS – domain troubleshooting
- Cloudflare – troubleshooting a slow website
