What should I do if DNS resolution is abnormal? Summary of common causes and handling methods

in the process of daily use of the network, many people have encountered the situation that the network connection is normal, but the webpage cannot be opened and the application content cannot be loaded. This is likely to be the cause of DNS resolution abnormalities. DNS resolution abnormalities will directly affect the conversion of domain names and Internet Protocol Addresses, resulting in devices unable to correctly locate network resources. This article will deeply analyze the common causes of DNS resolution abnormalities, and organize a system of troubleshooting and solutions to help you quickly get rid of network access difficulties and restore a smooth Internet experience.

What causes DNS resolution exceptions?

to solve the abnormal problem of DNS resolution, we must first clarify the incentives behind it, and the solutions corresponding to different reasons are also different.

1, local network fluctuations or line failures

when the line of the home or office network is loose, damaged, or the operator's network temporarily fluctuates, it will directly affect the transmission of DNS requests, which will cause DNS resolution abnormalities. For example, the poor contact of the router interface and the extrusion of the optical fiber line may lead to the interruption of DNS signal transmission and the prompt of resolution failure.

2, local DNS cache data error

device will store the resolved domain name information in the local cache in order to improve the access speed. If the cached data is damaged, expired, or tampered with by malicious software, it will cause subsequent domain name resolution requests to call wrong data and cause DNS resolution exceptions. This situation is more likely to occur after frequent switching of network environments.

3, public DNS server failure or congestion

many users default to using the public DNS server provided by the operator. Once the server has a hardware failure, suffered a network attack, or caused congestion due to excessive access, it will not be able to process the resolution request in time, and eventually cause DNS resolution exceptions. In addition, public DNS servers in some regions may have regional restrictions, which will also lead to resolution failure.

What are the basic troubleshooting methods for DNS resolution abnormalities?

encounter DNS resolution abnormalities, start with the basic troubleshooting steps, which can quickly eliminate most common problems and avoid complex operations.

1, check the network connection status

first check the network icon of the device to confirm whether there is an exclamation mark or disconnect logo. You can try to restart the router and light cat, and wait 30 seconds before reconnecting to the network. Many DNS resolution abnormalities caused by temporary network fluctuations can be solved in this simple way. At the same time check whether the network cable and fiber interface are plugged in tightly to rule out line contact problems.

2, refresh the local DNS cache

Windows users can press the Win + R key to open the run window, enter cmd to open the command prompt, then enter the ipconfig /flushdns command, press the Enter key to empty the local cache; Mac users can open the end point, enter sudo killall -HUP mDNSResponder command, verify the password and complete the cache refresh. After refreshing the cache, try to access the network to see if the DNS resolution exception disappears.

What is the advanced repair method of DNS resolution exception?

if the basic troubleshooting can not solve the DNS resolution exception, you need to use advanced repair methods, starting from the server settings and network configuration level.

1, manually replace the public DNS server

can choose public DNS servers commonly used at home and abroad, such as domestic 114.114.114.114, 223.5.5.5, foreign 8.8.8.8, 8.8.4.4. Take the Windows system as an example, open the network and sharing center, find the currently connected network, click Properties to select Internet Protocol version 4, manually enter the new DNS server address, save and restart the network to solve the DNS resolution abnormality caused by the failure of the original DNS server.

2, check local firewall or security software

excessive protection of some firewalls or security software may intercept normal DNS resolution requests, resulting in abnormal DNS resolution. You can temporarily turn off the firewall and security software and try to access the network. If you can open the webpage normally, you need to add DNS resolution permission rules in the security software, or adjust the protection level to the appropriate range.

4. How to prevent DNS resolution exceptions from happening again?

solve the current DNS resolution abnormality, taking preventive measures can reduce the probability of the problem recurring and ensure long-term stable network access.

1, regularly clean the local DNS cache

recommend manually cleaning the local DNS cache once a month to avoid outdated or incorrect cache data accumulation and reduce the occurrence of DNS resolution exceptions from the source. You can also use third-party tools to set up an automatic cleaning plan to improve maintenance efficiency.

2, configure multiple alternate DNS servers

when setting up the DNS server, in addition to the preferred address, configure 1-2 alternate addresses. When the preferred DNS server fails, the device will automatically switch to the backup server to avoid DNS resolution abnormalities caused by a single server problem and improve the stability of network access.

To sum up, DNS resolution abnormalities are common network problems, and their causes cover network lines, cached data, server status, etc. By basic investigation and positioning of the root cause of the problem, and then using the corresponding advanced repair methods, DNS resolution abnormalities can be quickly resolved. At the same time, preventive measures such as regular cache cleaning and configuration of backup servers can effectively reduce the probability of recurrence and make network access smoother.