What should I do if the domain name cannot be resolved? Summary of common reasons and handling methods

in the process of website operation or daily Internet access, many people have encountered the problem that the domain name cannot be resolved. It will directly lead to the failure of the website to open normally. For webmasters, it may affect business transformation, and for ordinary users, it will hinder information acquisition. Many people do not know where to start when encountering such problems. In fact, there are many reasons why the domain name cannot be resolved, covering the status of the domain name itself, DNS services, and local networks. This article will systematically sort out the common reasons why the domain name cannot be resolved, and give corresponding treatment methods to help you quickly troubleshoot and solve the problem and restore normal network access.

Common core reasons why domain names cannot be resolved?

to solve the problem that the domain name cannot be resolved, it is first necessary to clarify where the problem is, and the investigation from the core incentive can greatly improve the efficiency.

1, domain name status is abnormal

domain name status is the basic factor affecting the resolution. If the domain name is in the state of expired and not renewed, locked by the registry, and failed to pass the record, it will directly cause the domain name to fail to be resolved. For example, after the domain name expires, the registrar will suspend the resolution service of the domain name, and users will naturally not be able to access the website through the domain name; some domain names are locked by the registry due to illegal use, which will also lead to the failure of the resolution function.

2, DNS server configuration error

DNS server is the core carrier responsible for domain name resolution. If the A record and CNAME record of the DNS server are misconfigured, or the DNS server itself fails, the domain name cannot be resolved. For example, the IP of the server pointed to by the A record is filled in incorrectly, or the domain name associated with the CNAME record does not exist, which will make the resolution request unable to get a correct response; some small DNS servers are not stable enough, and outages will also cause resolution failure.

3, local network or device issues

In addition to domain name and DNS server problems, abnormalities in the local network or device may also cause the domain name to fail to resolve. For example, the local DNS cache expires or there are error records, which will prevent the device from getting the latest resolution information; the router DNS setting is wrong, or the local network operator's DNS server failure will also affect the normal progress of domain name resolution.

Second, the domain name can not resolve the domain name side investigation method?

when encountering the problem that the domain name cannot be resolved, the first thing to do is to check the status of the domain name itself, which is the most basic and most easily ignored link.

1. Query the current status of the domain name

can check whether the domain name is in a normal state through the background of the domain name registrar or the third-party domain name status query tool. Focus on the expiration time of the domain name, whether it is locked, the filing status and other information. If the domain name is found to have expired, the renewal needs to be completed in time; if it is in a locked state, contact the registrar to understand the reason and apply for unlocking; if the filing fails, the filing process needs to be completed as required.

2, check the domain name WHOIS information

WHOIS information contains key content such as domain name registrar, registration time, expiration time, DNS server, etc. By querying WHOIS information, it can confirm whether the DNS server configuration of the domain name is correct and whether the registration information of the domain name is normal. If you find that the DNS server configuration is wrong, you can directly modify it to the correct DNS server address in the registrar background.

Third, the domain name can not be resolved DNS side processing method?

DNS configuration is the core link of domain name resolution, and many problems that cannot be resolved by domain names are at this level, which needs to be carefully investigated and adjusted.

1, check DNS record configuration

log in to the DNS management background, check the A record, CNAME record, MX record and other configuration information one by one to ensure that the Internet Protocol Address or associated domain name pointed to by the record is accurate. For example, the A record should correspond to the public network IP of the website server, and the CNAME record should point to the domain name that has been resolved normally. If a configuration error is found, modify it in time and wait for the DNS record to take effect. Generally, the effective time ranges from 10 minutes to 24 hours.

2, replace the stable public DNS server

if the DNS server currently used is not stable enough and often has the problem that the domain name cannot be resolved, you can consider replacing it with a public DNS server. For example, domestic 114.114.114.114 and Alibaba Cloud 223.5.5.5, these public DNS servers have high stability and fast resolution speed, which can effectively reduce the probability that the domain name cannot be resolved.

4. The local side solution that the domain name cannot be resolved?

eliminate the problems of the domain name and DNS side, it is necessary to consider whether the local network or device has caused the domain name to be unresolved.

1, refresh the local DNS cache

local device will cache the resolved domain name information. If the cache record expires or there is an error, the domain name cannot be resolved. You can refresh the DNS cache through the command line tool. The Windows system can enter "ipconfig /flushdns" in the command prompt. The Mac system can enter "sudo dscacheutil -flushcache" at the end point. After refreshing, try to access the domain name. Many times it can solve the problem directly.

2, adjust the local DNS server settings

if the DNS server of the local router or device is set incorrectly, the domain name cannot be resolved. You can modify the local DNS server address to the public DNS server address, such as 114.114.114.114, restart the router or device after modification, and then test whether the domain name can be resolved normally.

To sum up, the problem of domain name unresolvable involves multiple levels such as domain name status, DNS configuration, and local network. The investigation needs to be gradually advanced from the domain name end to the DNS end and then to the local end. First confirm whether the domain name status is normal, then check the DNS record configuration, and finally check the local network and equipment problems. According to this logic, the cause can be quickly located and solved. In daily operations, the domain name status and DNS configuration should also be regularly checked to avoid the risk of domain name unresolvable in advance and ensure the stable access of the website.