A computer or phone may show a status of "connected," but the browser still fails to open websites. Sometimes only one site has issues, while other times almost all addresses are inaccessible. Situations like this often lead people to immediately restart the router, even though the source may lie with the DNS.
DNS stands for Domain Name System, which is a service that translates names like example.com into IP addresses that networks understand. Simply put, DNS works like an internet contact book. If the name lookup fails, the device may still be connected to Wi-Fi but doesn't know which server to contact.
Differentiate DNS Issues from Regular Internet Problems
The first step is not to change settings but to ensure the symptoms. DNS issues usually have patterns like the following:
- Wi-Fi or network cable status shows an active connection.
- Specific applications can still be used, but the browser fails to open website addresses.
- Websites can be accessed via IP address but not through the domain name.
- Messages like "DNS_PROBE_FINISHED_NXDOMAIN," "Server DNS address could not be found," or "Cannot find the server's IP address" appear in the browser.
- After switching networks, for example from Wi-Fi to a hotspot, the website works normally again.
These symptoms do not automatically prove that DNS is the cause. The website may be experiencing issues, the internet connection may be partially down, or the office network may be blocking certain domains. However, the above patterns are strong enough to start checking from the DNS.
Start with the Simplest Checks
1. Try Different Websites
Open two or three websites that are usually stable. If only one domain cannot be opened, the issue likely lies with that website, domain configuration, or specific blocking. If many websites fail to open simultaneously, checking DNS and local connection makes more sense.
2. Try Another Browser or Device
Open the same website using a different browser. If Chrome fails but Firefox works, the issue may be with the cache or browser settings. If all browsers on the computer fail, but the phone on the same network can access the website, the problem may only be with that computer.
3. Change Networks for Testing
Use your phone's hotspot for a few minutes. Do not make this a permanent solution yet; use it only as a comparison. If the website works normally through the hotspot but fails through home or office Wi-Fi, the issue likely lies with the router, the DNS from the internet provider, or local network policies.
Clear DNS Cache on the Device
Devices typically store temporary DNS query results to speed up future access. This cache can sometimes contain outdated or corrupted information, especially after a website moves servers or domain settings change.
Windows
Open Command Prompt as a regular user, then run the following command:
ipconfig /flushdnsIf successful, Windows will display a message that the DNS cache has been cleared. Close and reopen the browser, then try accessing the same website again.
macOS
On macOS, the command may vary depending on the system version. One commonly used command is:
sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponderThe terminal will prompt for the account password. When typing the password, characters usually do not appear. This is normal. After the process is complete, repeat the test in the browser.
Android and iPhone
Phones do not always provide a specific button to clear the DNS cache. The safest way is to enable airplane mode for a few seconds, turn it off again, and then try accessing the website again. If that doesn't work, restart the device and forget the Wi-Fi network before reconnecting.
Check DNS Settings
If clearing the cache does not resolve the issue, the DNS used by the network may be slow or experiencing disruptions. You can try public DNS from a trusted provider, but understand the consequences: your DNS requests will be sent to that provider, not to the network's default DNS.
Some commonly used public DNS services provide both IPv4 and IPv6 addresses. When changing them, enter the addresses carefully and note the original settings for easy restoration. Do not change DNS if the device is on a corporate, school, or organizational network without administrator permission, as DNS may be used for security policies and internal filtering.
In Windows, these settings are usually found in Settings, then under network, adapter properties, and DNS configuration. On macOS, the settings are located in System Settings, the active network, then under DNS. Menu names may vary slightly depending on the system version.
Use Commands to Identify the Source of the Problem
If you want to check more technically, you can compare the DNS lookup results with the website address.
On Windows, run:
nslookup domain-name.comOn macOS or Linux, use:
dig domain-name.comIf these commands fail to find the address, but the internet connection is generally still active, DNS should be suspected. However, if DNS returns an IP address and the website still cannot be opened, the issue may lie with the firewall, website server, HTTPS certificate, proxy, or network path.
Don't Forget to Check the Browser and Router
Modern browsers can have their own DNS cache. Closing all browser windows and reopening them may sometimes be enough to test this. You can also try a private window, but private mode does not automatically fix DNS; this feature only helps differentiate issues with cache, cookies, or extensions.
If all devices at home experience the same symptoms, restart the router and modem properly. Turn off the devices, wait about a minute, then turn them back on. If the problem persists, check the router's administration page to see if the DNS is locked, replaced by old configurations, or directed to servers that are no longer available.
What Does This Mean for Us?
Internet connectivity is not just about the presence or absence of a Wi-Fi icon. There are several layers that must work sequentially: devices must connect to the router, the router must have internet access, DNS must translate domain names, and then the connection must reach the target server. Understanding this sequence helps us avoid random solutions.
A practical order of checks is:
- Test several websites and devices.
- Try another network as a comparison.
- Clear the device's DNS cache.
- Check DNS and browser settings.
- Restart the router if the problem occurs on multiple devices.
- Contact the internet provider or network administrator if disruptions persist.
Avoid installing "internet booster" applications that promise instant fixes. Such applications often only change DNS, add ads, or request unnecessary permissions. For DNS issues, simple checks and reversible changes are usually safer than installing unclear tools.
– Rio Yotto @rioyotto