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How to Test DNS Resolution

Learn how to test DNS resolution with nslookup, ping, and public DNS servers.

Beginner10 min

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DNS resolution diagram showing a domain name resolving to an IP address. — DNS resolution translates website names into IP addresses devices can reach.

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What Is DNS Resolution?

DNS (Domain Name System) resolution is the process of translating a website name, such as google.com, into an IP address that computers use to communicate.

For example:

google.com -> 142.250.190.14

If DNS resolution fails, websites may not load even when your internet connection is working.

Example

Use this section as your baseline before working through the symptoms, commands, and fixes below.

Symptoms of DNS Issues

Common symptoms include:

Websites will not load

"DNS Server Not Responding" errors

"Server Not Found" messages

Some websites work while others do not

Slow website loading times

Method 1: Test DNS with nslookup

Open Terminal or Command Prompt and run:

nslookup google.com

Successful result:

Server:  192.168.0.1
Address: 192.168.0.1#53

Non-authoritative answer:
Name:    google.com
Address: 142.250.190.14

This confirms DNS is resolving the domain name correctly.

Failed result:

DNS request timed out.
timeout was 2 seconds.

Another failed result may look like this:

*** Can't find google.com: Server failed

This indicates a DNS problem.

Method 2: Test with Ping

Run:

ping google.com

Successful result:

Pinging google.com [142.250.190.14] with 32 bytes of data:
Reply from 142.250.190.14

Notice that the hostname was converted into an IP address.

Failed result:

Ping request could not find host google.com.

This usually means DNS resolution is failing.

Method 3: Compare DNS Servers

Test using a public DNS server.

Google DNS:

nslookup google.com 8.8.8.8

Cloudflare DNS:

nslookup google.com 1.1.1.1

If these work but your router's DNS server does not, the issue is likely with your ISP or local DNS server.

Method 4: Check Current DNS Servers

Windows:

ipconfig /all

Look for DNS server entries like:

DNS Servers . . . . . . . . . : 8.8.8.8
                                1.1.1.1

macOS:

scutil --dns

Alternative macOS command:

networksetup -getdnsservers Wi-Fi

Linux:

cat /etc/resolv.conf

Troubleshooting DNS Problems

Flush DNS Cache:

Windows:

ipconfig /flushdns

macOS:

sudo dscacheutil -flushcache

sudo killall -HUP mDNSResponder

Change DNS Servers:

Try switching to:

Cloudflare: 1.1.1.1 and 1.0.0.1

Google DNS: 8.8.8.8 and 8.8.4.4

Restart Network Equipment:

Power off the modem and router

Wait 30 seconds

Power them back on

Test DNS again

Key Takeaway

If nslookup successfully returns an IP address, DNS resolution is working correctly. If it fails, focus on your DNS server settings, router configuration, or ISP DNS service.