How to Fix DNS Error: Step-by‑Step Guide

A DNS error happens when a system cannot translate a website’s domain name into its matching IP address. This translation process is needed for connecting to sites. DNS errors can result from:

• Incorrect or outdated DNS records. For example, name server records may be wrong, or A records may not point to the current IP address.
• Time-to-live (TTL) problems. High TTL values may delay the spread of changes, and low TTL values may cause too many queries, which sometimes results in records being lost.
• DNS DDoS attacks. If a DNS server comes under a distributed denial of service attack, it may not respond to requests, so users face errors.
• DNS cache poisoning. Hackers may insert false data into a DNS cache so that it sends you to a dangerous site instead of the real one.
• High latency. If there is a delay in DNS resolution, such as when the server is far from your location or is affected by network problems, the process can fail.

How to Identify If You’re Facing a DNS Issue

You can spot DNS issues with these signs:

• Persistent messages like “Server not found,” “DNS resolution failed,” or “Unable to resolve the domain name.”
• Slow website loading. If a site takes longer than usual to load, the Domain Name System may be to blame.
• Inconsistent connectivity. Some devices access the site without trouble, and some cannot.
• Diagnostic tools. Using commands like nslookup, dig, or host helps you look up DNS records and spot issues.

Quick Fixes You Can Try Immediately

Restart your device

Restarting your computer, phone, or tablet can clear out stuck processes, release old DNS data, and reconnect network services.

Switch browsers or use incognito mode

Switching browsers or turning on incognito or private mode rules out browser extensions or local browser cache as the source of the problem.

Test on another device or network

Open the website or service using a different device on the same network, or take your current device to a different WiFi or use mobile data. If the error happens on only one device, the problem is likely with its DNS cache or settings.

Clear DNS Cache – Commands for Every Platform

Clearing DNS cache can remove corrupted or outdated records.

On Windows

1. Open Command Prompt as an administrator.
2. Type each of these and press Enter after each:
      ipconfig /flushdns
   ipconfig /registerdns
   ipconfig /release
   ipconfig /renew
      This sequence clears the local cache, refreshes the computer’s DNS registration, and resets the network address.

On macOS

• Open Terminal.
• If you use macOS Sierra or later, type:
     sudo killall -HUP mDNSResponder
• For El Capitan or earlier, use:
     sudo discoveryutil udnsflushcaches
     You may need your admin password.

In Google Chrome

• Go to chrome://net-internals/#dns in your browser.
• Click on “Clear host cache.” This flushes Chrome’s DNS cache only.

Renew IP and Network Settings

Release and renew IP address

On Windows, the following steps renew your IP address:

• Open Command Prompt as an administrator.
• Type:
     ipconfig /release
   ipconfig /renew
     This releases the current IP and requests a new one from the router.

Reset Winsock and TCP/IP stack

If network protocols are misconfigured, resetting may help:

1. In Command Prompt as administrator, enter:
      netsh winsock reset
   netsh int ip reset

This will require a reboot to take full effect.

Change DNS Servers to Reliable Public Options

Your system usually uses the DNS provided by your Internet Service Provider, but sometimes these are slow or unreliable. Using public DNS servers can fix the issue.

Google DNS (8.8.8.8 / 8.8.4.4)

Google’s DNS servers are actively monitored for uptime and speed. To use them, add these addresses to your device’s network settings.

Cloudflare DNS (1.1.1.1 / 1.0.0.1)

Cloudflare DNS is known for quick response and privacy. Set your DNS server addresses to these, following the same steps you would for Google DNS.

How to set DNS on Windows, macOS, Android, iOS

• Windows: Open Network and Sharing Center. Select your connection. Click Properties. Choose “Internet Protocol Version 4 (TCP/IPv4)” and then click Properties. Type the DNS addresses in the fields.
• macOS: Go to System Preferences, choose Network, select your network connection, click Advanced, then click the DNS tab and enter the server addresses.
• Android: Open Settings, tap Wi-Fi, choose your network, then select “Modify network.” Find “Advanced options” and change DNS 1 and 2.
• iOS: Open Settings, tap Wi-Fi, pick your network, tap the “i” button, scroll to DNS, and change the entries.

Save and reconnect to the Internet after changes.

Restart and Reconfigure Your Router

Power cycle and firmware updates

Turn off your router, unplug it for 30 seconds, then plug it in and turn it back on. This clears cached data that may be causing problems. Log in to the router admin panel and check for firmware updates. Apply updates as needed.

Check router DNS, DHCP, and IPv6 settings

Log into your router’s admin interface. Confirm it uses the correct DNS addresses, or try setting public DNS options. Check that DHCP is working and distributing the right information to your network. If you do not use IPv6, you may want to turn it off or confirm the settings are correct.

Disable VPN, Antivirus, and Firewalls Temporarily

VPNs and security software can block or interfere with normal DNS traffic. To see if this is happening, turn off your VPN and suspend your antivirus or firewall. Try to access the site again. Remember to reactivate your security tools after testing.

Inspect Hosts File and Local DNS Overrides

The hosts file takes priority over DNS lookups. On Windows, it is stored at C:/Windows/System32/drivers/etc/hosts. On macOS, it is at /etc/hosts. Open the file with an editor and look for lines that match the website or IP you are having trouble with. Remove or fix any wrong entries, then save the file. You may need administrator rights to edit.

For Website Owners: Check DNS Records and TTL

Check DNS Records

Examine all DNS record types, such as A, MX, or CNAME, and make sure they are accurate. Use online tools to see if the internet’s view matches what you expect.

Check TTL

Set TTL values with care. A high TTL can slow down the visibility of your changes. A very low TTL can make your server answer too many queries. Use a value from one hour up to twenty-four hours in most cases.

When to Contact ISP or Hosting Support

If the above steps do not solve the problem, get help from your provider in these cases:

• The issue continues on every device or after trying fixes.
• Your network setup is complex, or you are not sure how your DNS records should be set.
• A DDoS attack is hitting your services.

Preventing Future DNS Errors

Keep DNS TTL moderate

Select a moderate TTL for your records. Avoid very high or low settings.

Use public DNS as fallback

Program your devices or router to use a public DNS service as a secondary option if your main service fails.

Regularly update firmware

Check for new firmware for your router and network devices every few months, and update as soon as it is tested and available.

Summary & Final Checklist

To troubleshoot DNS errors, go through this list:

• Check if the correct name servers are set.
• Confirm your domain registration is valid.
• Review all DNS records for errors or typos.
• Clear the DNS cache on all devices you use.
• Set reliable DNS servers, and use a public fallback.
• Update router and network device firmware on schedule.
• Check the hosts file for incorrect lines.
• Set a practical TTL, not too long or short.

Frequently Asked Questions

How do I flush DNS on a Mac?

For macOS Sierra and newer, open Terminal and type:
sudo killall -HUP mDNSResponder
For El Capitan or before, use:
sudo discoveryutil udnsflushcaches

What are the best public DNS servers?

Google DNS (8.8.8.8 / 8.8.4.4) and Cloudflare DNS (1.1.1.1 / 1.0.0.1) are fast and reliable.

Will changing DNS slow down my connection?

Public DNS servers like Google and Cloudflare do not normally slow your connection. Often, they speed it up.

Can DNS errors be caused by malware?

Malware can change DNS settings or poison the cache to redirect users, resulting in DNS errors.

Why did only one device have the issue?

This may be from a problem with device-specific DNS settings, a corrupted DNS cache, or mismatched entries in its hosts file.

How long does DNS propagate after changes?

Propagation speed depends on the record’s TTL. Changes may be seen in minutes or several hours.

When should I reset my router?

Reset the router after other methods fail or if you made major changes to network or DNS configuration.

Does IPv6 cause DNS failures?

IPv6 does not cause DNS errors on its own, but incorrect IPv6 settings can create DNS problems.

What’s the difference between ISP and public DNS?

ISP DNS servers are provided by your internet company. Public DNS servers, such as Google and Cloudflare, are managed by other organizations and are often more reliable or fast.

My site shows NXDOMAIN ,  what does it mean?

NXDOMAIN signals that the domain name does not exist in DNS. The reason could be a typing error, a domain that is not registered, or missing or wrong DNS records.

The post How to Fix DNS Error: Step-by‑Step Guide appeared first on GreenGeeks.