What should I do if the DNS server is abnormal? Full analysis of the reasons 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 they cannot open the website, load the page card or even prompt that they cannot be accessed. This is most likely caused by the abnormality of the DNS server. As the "domain name translator" in the network, DNS is responsible for converting the easy-to-remember domain name into the Internet Protocol Address that the computer can recognize. Once it is abnormal, the entire network access link will be blocked. This article will deeply dismantle the reasons for the abnormality of the DNS server, and provide a full range of troubleshooting and solutions to help you quickly restore a smooth network experience.

What are the common causes of DNS server abnormalities?

to solve the abnormal problem of DNS server, we must first identify the root cause of the problem, different incentives correspond to different solutions, the following to sort out several of the most common triggers.

1, local network fluctuations or line failures

this is one of the common reasons for DNS server abnormalities. For example, the router at home is overheating for a long time, the network cable is loose or damaged, and the operator temporarily overhauls the line, etc., which will cause the device to fail to connect to the designated DNS server normally, and then the domain name resolution fails. Such abnormalities are usually accompanied by unstable and intermittent network connections.

2, the DNS server itself fails

if the public DNS server or the operator's own DNS server is down, maintained or overloaded, it will directly cause DNS server abnormalities. For example, the DNS server of operators in some regions is attacked by network attacks, or the server hardware is aging and faulty, which will cause domain name resolution requests to fail to respond normally.

3, the local network configuration error

enter the wrong DNS address manually, or the network configuration of computers, mobile phones and other devices is tampered with by malicious software, it will also cause DNS server abnormalities. For example, some malicious programs will tamper with the DNS configuration of the device and point it to a false server, causing users to be unable to access regular websites normally, and even be guided to phishing pages.

How to quickly troubleshoot DNS server abnormalities?

when it is suspected that the DNS server is abnormal and causes network problems, it cannot operate blindly, and it is necessary to locate the problem through scientific troubleshooting steps in order to accurately solve it.

1, use the ping command to detect connectivity

enter the ping command in the command prompt of the computer, first ping a known public Internet Protocol Address, such as Baidu's Internet Protocol Address 14.215.177.38. If it can be pinged normally, it means that the network link itself is no problem, and the problem is most likely in the DNS resolution link. If the ping fails, it means that the network connection itself is faulty, not the DNS server is abnormal. Then ping common domain names, such as www.baidu.com, if it cannot be pinged but can ping IP, it can be determined that the DNS server is abnormal. Resolve failure.

2, replace the DNS server test

temporarily replace the DNS address of the device with public DNS, such as Alibaba Cloud's 223.5.5.5 or Google's 8.8.8.8, and then try to access the website. If it can be opened normally, it means that the original DNS server used is abnormal; if it is still inaccessible, it may be a problem with the local network configuration or hardware.

What are the basic repair methods for DNS server abnormalities?

for common DNS server abnormal problems, we can try some basic repair operations first, most simple exceptions can be solved by these methods.

1, restart network devices and end point

this is one of the most basic and effective ways to solve DNS server abnormalities, first turn off the computer, mobile phone and other end point devices, then unplug the power supply of the router and light cat, wait 10 to 15 seconds to re-power and start, so that the device can re-obtain the network configuration. Many times, the cache or temporary failure caused by the long-term operation of the device will be automatically cleared after restart, and the DNS server abnormality will disappear.

2 Repair local DNS cache

computer will automatically cache the resolved domain name information. If the cache is damaged or expired, it will also cause a DNS server exception. In Windows systems, you can open the command prompt, enter the ipconfig /flushdns command, and after execution, you can clear the local DNS cache and let the device request the domain name resolution to the server again, so as to solve the exception caused by the cache problem.

4. Advanced solutions to DNS server abnormalities?

if the underlying approach fails to resolve DNS server anomalies, you need to take some advanced measures to fix problems with the configuration or the server itself.

1, manually replace reliable DNS servers

If it is determined that the DNS server is abnormal due to the failure of the original DNS server itself, it can be manually replaced with a stable public DNS server. At present, the commonly used public DNS in China are Alibaba Cloud's 223.5.5.5 and Tencent's 119.29.29.29. These server nodes are widely distributed and have high stability, which can effectively reduce the probability of DNS resolution failure. When replacing, just manually modify the DNS address to the corresponding value in the network settings of the device.

2, check and repair network configuration

If the DNS server is abnormal due to the wrong configuration of the local network, you need to check the network settings of the device. For example, in the Windows system, open the Network and Sharing Center, find the currently connected network, check the IPv4 properties, confirm whether the DNS address is correct, if the address is found to be wrong or tampered with, modify it to the correct address in time; if it is automatically obtained DNS, you can also try to switch to manual settings to avoid automatically obtaining abnormal DNS addresses.

To sum up, DNS server abnormalities are common network problems, and their causes cover network fluctuations, server failures, configuration errors, and other aspects. To solve the problem, you need to check the root cause through ping commands, server replacement, etc., and then take measures such as restarting the device, clearing the cache, changing the DNS address, and repairing the configuration according to the specific situation. As long as you follow the correct steps, you can quickly locate and solve DNS server abnormalities and restore a smooth network access experience.