What should I do if the website DNS is unavailable? Detailed reasons and quick fixes

when you are ready to visit a commonly used website but encounter a loading failure, the browser pops up a prompt that cannot resolve the domain name, it is most likely that you have encountered the problem of website DNS unavailability. This failure will not only affect the web page access experience of ordinary users, but also directly cause user churn and business losses for webmasters and enterprises that rely on online traffic. This article will deeply disassemble the reasons behind the unavailability of website DNS, and combine practical fixes to take you step by step to troubleshoot and solve such domain name resolution failures, so that the website can return to normal access.

What are the common causes of website DNS unavailability?

want to efficiently solve the problem of website DNS unavailability, we must first find the root cause of the failure, and the repair direction corresponding to different incentives is quite different.

1, local DNS cache exception

the local device will automatically store the recently visited domain name resolution records. When these cached data are damaged or expired and not updated, the DNS unavailable prompt of the website will be triggered. For example, if you just modified the DNS configuration of the website, but the local cache still stays on the old record, the device will not be able to obtain the new resolution address, resulting in access failure.

2, DNS service provider node failure

if the DNS service provider you use has server downtime, node maintenance or network congestion, it will also cause the website DNS to be unavailable. For example, some niche DNS service providers have limited node coverage. Once the core node fails, users in large areas cannot resolve the domain name normally.

3, domain name resolution misconfiguration

the webmaster sets the resolution record in the background of the domain name management, if the record type is wrong, the Internet Protocol Address is filled in incorrectly, and the TTL value is set irrationally, it will directly cause the DNS of the website to be unavailable. For example, if the A record is mistakenly filled in as a CNAME record, or the server Internet Protocol Address itself cannot be accessed normally, the resolution request cannot be responded correctly.

2. What are the local troubleshooting steps for website DNS unavailability?

encounter the situation that the website DNS is not available, start troubleshooting from the local device first, which can quickly eliminate most common faults and avoid unnecessary service provider communication costs.

1, refresh the local DNS cache

this is the basic operation to solve the DNS unavailability of the website. Windows users can open the running window by pressing the Win + R key, enter cmd into the command prompt, and then enter the ipconfig /flushdns instruction to perform cache refresh. Mac users can enter the sudo dscacheutil -flushcache instruction through the end point to complete the operation. After the refresh is completed, try to access the website again, and most of the failures caused by cache exceptions can be solved.

2 Switching public DNS servers

if the DNS of the website is still unavailable after refreshing the cache, you can try to switch to the public DNS server, such as domestic 114.114.114.114, Alibaba Cloud 223.5.5.5, or foreign 8.8.8.8. These public DNS nodes cover a wide range and have strong stability, which can effectively avoid the resolution problems caused by the failure of the original service provider node.

3, detect local network connectivity

use the ping command to detect whether the local network can normally connect to external servers, such as ping 8.8.8.8, if there is a serious packet loss or completely unable to connect, it means that the local network failure indirectly caused the website DNS is not available, then you need to check the router settings or contact network operators to solve network problems.

3. Service provider repair method for website DNS unavailable?

if the problem of website DNS unavailability is not solved after local troubleshooting, it is necessary to troubleshoot the configuration problem from the background of the domain name service provider or DNS service provider.

1, check the validity of the domain name resolution record

log in to the domain name management background, check the parsing entries such as A records and CNAME records one by one, and confirm whether the record type, target address and TTL value settings are correct. If an error is found, modify it in time, wait 10-30 minutes for the parsing records to be synchronized across the network, and then test whether the website still has the situation that the website DNS is not available.

2, switch DNS service provider node

if the DNS service provider node failure is used to cause the website DNS is not available, you can switch to other available nodes in the service provider background, such as some Cloud as a Service providers provide multi-regional node selection, priority is given to nodes closer to the client base, which can not only improve the resolution speed, but also reduce the impact of node failure.

3, open DNS resolution monitoring alarm

In order to avoid the sudden failure of the website DNS unavailable again in the future, the DNS resolution monitoring function can be turned on in the background of the service provider, and the abnormal alarm notification can be set. When the resolution delay is too high, the node fails, etc., the system will notify you by text message or email as soon as possible, so that you can intervene in the early stage of the failure.

To sum up, the troubleshooting of website DNS unavailable needs to be gradually advanced from the local to the service provider. First, solve the problem at the local level by refreshing the cache and switching the public DNS, and then check the resolution records and switch the service provider node to deal with the background configuration failure. It is also necessary to regularly check the validity of DNS configuration and turn on monitoring alarms to minimize the probability of website DNS unavailable and ensure the stable access of the website.