Why does flush DNS often fail to work?

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Solution 1

Most likely the caching issue you are seeing is related to the DNS servers your computer is configured to use. This configuration can be either done manually (to use Google or OpenDNS) or automatically (via DHCP, which uses the DNS servers your ISP recommends). Either way, you can see what your computer is using by following these steps. These servers do cache DNS information for usually hours, sometimes days.

If you already cleared the Windows DNS cache, and you are positive the DNS servers used by your computer uses have already been updated* with new information, then the DNS records are being cached in your browser. Learn how to clear the DNS cache for all the browsers.

*here is a good tool to find out, just input the DNS server your computer is using in the "server" field

Solution 2

The Windows flushdns option only clears your local DNS cache. The next time you request a web address your system will make a new query to your remote DNS servers for the IP address. If your remote DNS servers haven't picked up the new IP address then your system will re-cache the old IP locally.

There's generally nothing you can do to force remote DNS servers to refresh their cache, but you could move away from using your default DNS servers (usually hosted by your ISP) and move to public DNS servers like those hsoted by Google or OpenDNS. These tend to refresh their DNS cache more quickly than many ISPs.

As an additional note for future reference, if you have control over your domain's DNS records then it may be worth setting a lower TTL to suggest they get crawled more frequently, especially if you expect them to be changing in future.

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user4234
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Updated on September 18, 2022

Comments

  • user4234
    user4234 over 1 year
    C:\Windows\system32>ipconfig /flushdns
    
    Windows IP Configuration
    
    Successfully flushed the DNS Resolver Cache.
    
    C:\Windows\system32>ping beautyadmired.com
    
    Pinging beautyadmired.com [xxx.45.62.2] with 32 bytes of data:
    Reply from xxx.45.62.2: bytes=32 time=253ms TTL=49
    Reply from xxx.45.62.2: bytes=32 time=249ms TTL=49
    Reply from xxx.45.62.2: bytes=32 time=242ms TTL=49
    Reply from xxx.45.62.2: bytes=32 time=258ms TTL=49
    
    Ping statistics for xxx.45.62.2:
        Packets: Sent = 4, Received = 4, Lost = 0 (0% loss),
    Approximate round trip times in milli-seconds:
        Minimum = 242ms, Maximum = 258ms, Average = 250ms
    

    My site should point to xx.73.42.27.

    I change the name server. It's been 3 hours. It still points to xxx.45.62.2.

    Actually what happen after we change name server anyway? Wait for what? I already flush DNS. Why it still points to the wrong IP?

    Also most other people that do not have the DNS cache also still go to the wrong IP.

  • Pacerier
    Pacerier almost 9 years
    Any disclaimers for the tool?
  • Gaia
    Gaia almost 9 years
    What kind of disclaimers? No, I am not associated with them. Are you interested in the their privacy policy? help.org/privacy-policy