What should I do if the DNS server is unavailable? Reasons and quick solutions

when using a computer or mobile device to surf the Internet on a daily basis, many people have encountered situations where web pages are stalled and pop-up windows indicate network abnormalities. Among them, the unavailability of DNS servers is one of the most common types of failures. This problem can cause the device to fail to resolve the domain name properly, which in turn cannot access various websites, seriously affecting the efficiency of work and play. This article will delve into the potential reasons why DNS servers are unavailable, and provide several sets of proven and fast treatment methods to help you pinpoint the problem and quickly restore the network connection. It can be easily operated without professional technical background.

What are the common causes of DNS server unavailability?

want to efficiently solve the problem that the DNS server is not available, we must first clarify the root cause of the failure, and the repair methods corresponding to different reasons are quite different.

1, network hardware running abnormally

as the core hardware of the network connection, the router or light cat may have cache overload and program card after long-term operation, which is one of the common reasons for the unavailability of the DNS server. In addition, the loosening of the hardware interface and the damage of the network cable will also lead to the interruption of network signal transmission, which indirectly causes DNS resolution failure.

2, the local DNS setting error

some users manually modify the network settings, the wrong DNS address may be entered by mistake, or the valid address is not timely updated after the static DNS is turned on, resulting in the device cannot connect to the available DNS server. In addition, if the DNS address automatically obtained by the system has a regional network failure, it will also trigger the DNS server unavailable prompt.

3, network operator service failure

when the operator's DNS server in the area is maintained, upgraded, or has a hardware failure, it will cause a large number of users in the area to have the problem that the DNS server is not available. In this case, the device itself and the network hardware are not faulty and can only wait for the operator to repair the service.

What are the basic troubleshooting methods for DNS server unavailability?

quickly locate the problem through the basic troubleshooting steps before making complex settings modifications, which can save a lot of fault processing time and avoid invalid operations.

1, check the network hardware connection status

first check the indicator status on the router and light cat. If the network signal light flashes abnormally, you can try to re-plug and unplug the network cable to ensure that the interface connection is firm. Then restart the router and light cat, wait 2 to 3 minutes for the device to fully restart, and then test whether the network is restored. This operation can solve most DNS server unavailability problems caused by hardware cache.

2, switch network environment verification fault

If you use WiFi to surf the Internet, you can try to switch to the mobile phone hotspot network, or directly connect to the light cat test with a network cable. If the problem that the DNS server is not available after switching the network disappears, it means that the fault is on the original WiFi network or router; if the problem still exists, it is most likely a problem with the local settings of the device or the service of the operator.

What are the quick fixes for unusable DNS servers?

after completing the basic investigation, for different root causes of failure, corresponding repair methods can be used to quickly solve the problem that the DNS server is not available.

1, reset the local DNS cache

device has been online for a long time, the local DNS cache may store expired or incorrect domain name resolution records, which can cause the DNS server to be unavailable. On Windows systems, you can quickly empty the local DNS cache by executing the "ipconfig /flushdns" command from the command prompt; on Mac systems, you can execute the "sudo killall -HUP mDNSResponder" command in the end point to complete the cache reset.

2, modify the DNS server address

If the automatically obtained DNS address cannot be used, you can manually switch to the public DNS server address, such as domestic 114.114.114.114, Ali's 223.5.5.5, or foreign 8.8.8.8. When modifying, you need to enter the device network settings interface, find the DNS server settings option, change the automatic acquisition to manual input, fill in the above public DNS address and save the settings.

What is the advanced troubleshooting scheme for DNS server unavailability?

if the basic repair method cannot solve the problem that the DNS server is not available, you can try the advanced troubleshooting solution to further locate the deep fault.

1 Detect DNS server connectivity

use the command prompt or end point to execute the "ping target DNS address" command. If the timeout or packet loss rate is too high, it means that the DNS server cannot connect normally and needs to be replaced with another available DNS address. If the ping test is normal but still prompts that the DNS server is unavailable, it may be that the device firewall or security software intercepted the DNS request.

2, check firewall and security software settings

some security software in order to protect the equipment cyber security, may mistakenly determine the normal DNS resolution request as a risk operation and intercept. You can temporarily turn off the firewall and security software, and then test whether the network returns to normal. If the fault disappears, you need to add a whitelist of DNS server addresses in the security software to avoid subsequent problems of DNS server unavailability.

To sum up, DNS server unavailability is a common network failure, which causes hardware operation, setting errors, operator services and other aspects. When encountering such problems, you can first locate the root cause of the fault through basic troubleshooting, and then try to reset the cache, modify the DNS address, check the security software and other repair methods in turn. As long as you follow the steps one by one, you can quickly restore the normal domain name resolution function of the network and access various websites smoothly again.