How to detect DNS abnormalities? 3 practical detection methods to share

in daily network use, many people have encountered slow loading of web pages, domain names cannot be resolved or even completely disconnected from the network. In addition to broadband line problems, DNS abnormalities are common causes of such failures. As a bridge between domain names and Internet Protocol Addresses, the stability of DNS directly affects the network access experience. This article will share practical detection methods from multiple dimensions, teach you to accurately judge DNS abnormalities and troubleshoot problems, and help you quickly restore a smooth network connection.

Use the ping command to determine whether DNS is abnormal?

ping command is the most basic network detection tool, through which it can preliminarily determine whether there is a DNS resolution fault, the operation is simple and easy to use, suitable for all users to quickly troubleshoot.

1, first ping common public domain name

open the command prompt or end point of the computer, enter the common public domain name such as ping www.baidu.com, and wait for the return result. If there is a prompt that request timed out or the host cannot be found, it means that there may be a DNS resolution problem; if the Internet Protocol Address and delay data can be returned normally, it means that the current DNS resolution is basically normal. It should be noted that some websites may have disabled the ping service. At this time, you can test again with several different domain names.

2, and then ping the corresponding Internet Protocol Address

if the ping domain name fails, you can try to ping the known Internet Protocol Address corresponding to the domain name, such as Baidu's public IP 110.242.68.3. If the ping Internet Protocol Address can be connected normally, it means that there is no problem with the network line itself, and the point of failure is indeed in the DNS resolution process; if the ping IP also fails, it is most likely a problem with the broadband line or router, not an abnormal DNS. Through this comparison, it is more accurate to determine whether the DNS is the source of the failure.

Second, use the nslookup command to determine the DNS resolution fault

nslookup command is a tool specially used for DNS detection, which can directly view the detailed process and results of domain name resolution. It is more professional than the ping command and can deeply determine whether the DNS resolution is normal.

1, default DNS server resolution detection

enter nslookup www.baidu.com in the command prompt, the system will return the DNS server address currently used by default, and the Internet Protocol Address obtained by the server's resolution of the domain name. If an exception prompt such as "server unknown" or "non-authoritative reply" is returned, or the resolved Internet Protocol Address obviously does not meet expectations, it means that the DNS server currently in use has an abnormality and needs to be further investigated.

2, specify public DNS server comparison

In order to more accurately determine whether the DNS is abnormal, you can specify the public DNS server for resolution testing, such as entering nslookup www.baidu.com 8.8.8.8 and using Google public DNS for resolution. If the public DNS can be resolved normally after specifying, it means that there is a problem with the original DNS server; if it still cannot be resolved after specifying, it may be a problem with the local network settings or the domain name itself. At this time, you need to further check the network configuration.

three, by changing the DNS server to determine the root cause of DNS abnormality

the initial detection found that there may be DNS abnormalities, replace different DNS servers for testing, can quickly locate the problem is the DNS server itself, or the problem of the local network configuration.

1, replace with a public DNS server

common public DNS servers are Google's 8.8.8.8, domestic 114.114.114.114, etc., enter the network settings interface of the computer or router, and replace the default DNS address with these public DNS. After the replacement, try to access the webpage that cannot be opened before, if it can be loaded normally, it means that the original DNS server is faulty, and it is judged that the root cause of the DNS abnormality is on the server side; if it is still inaccessible, it may be a problem with the local network configuration, such as network interface card driver failure or router setting error.

2, replaced by the operator's exclusive DNS

if the problem persists after replacing the public DNS, you can try to replace the exclusive DNS server address provided by the local operator, which can generally be queried through the operator's official website or customer service. The operator's exclusive DNS is usually optimized for the local network, and the resolution speed is faster and more stable. If it returns to normal after replacement, it means that the previous public DNS may not be compatible with the local network; if it still cannot be solved, it is necessary to further investigate the problem of the local network hardware or system settings.

4. Use professional tools to judge the stability of DNS resolution

for users who need to monitor DNS status for a long time, professional DNS detection tools can more comprehensively judge the stability and speed of DNS resolution and provide more detailed fault data.

1, use the DNS Benchmark tool

DNS Benchmark is a free professional tool that can automatically test the resolution speed, stability and success rate of multiple public DNS servers, and display the results through intuitive charts. After running the tool, it will analyze a large number of domain names and finally give a score ranking to help you judge the performance of DNS servers. At the same time, it can also detect whether the DNS currently in use has abnormal conditions such as high resolution latency and low success rate.

2, use the webmaster platform DNS detection tool

online DNS detection tool provided by various webmaster platforms, it can resolve and test the designated domain name from nodes in different regions, which is suitable for website administrators to judge whether the global resolution of DNS is normal. After entering the domain name to be detected, the tool will display the resolution results of multiple nodes across the country and even the world. If the resolution fails or the resolution error occurs in some regions, it means that the global configuration of DNS is abnormal, and the DNS server settings or domain name resolution records need to be adjusted.

sum up, judging DNS abnormalities can be done step by step from basic commands to professional tools, first through ping and nslookup for preliminary detection, then by replacing the DNS server to locate the root cause, and finally with professional tools for comprehensive monitoring. These methods cover the different needs of individual users to enterprise administrators, and can help you quickly and accurately find DNS failure points and restore a stable network access experience.