Isolated ISP DNS issues preventing connections to Windows Update service

Windows Update customers were recently affected by a network infrastructure event on January 29, 2019 (21:00 UTC), caused by an external DNS service provider’s global outage. A software update to the external provider’s DNS servers resulted in the distribution of corrupted DNS records that affected connectivity to the Windows Update service. The DNS records were restored by January 30, 2019 (00:10 UTC), and the majority of local Internet Service Providers (ISP) have refreshed their DNS servers and customer services have been restored.

 If you are still unable to connect to Windows Update services due to this problem, please contact your local ISP or network administrator and refer them to this KB which will help them resolve the DNS issue for you.

You can connect your device to the internet and open a command prompt (Start Menu > Run > cmd) and then run each of these commands:

C:\>nslookup sls.update.microsoft.com 
C:\>nslookup fe2.update.microsoft.com 
C:\>nslookup fe3.delivery.mp.microsoft.com 
C:\>nslookup au.download.windowsupdate.com 
C:\>nslookup sls.update.microsoft.com.nsatc.net 
C:\>nslookup fe2.update.microsoft.com.nsatc.net 
C:\>nslookup fe3.delivery.dsp.mp.microsoft.com.nsatc.net 
C:\>nslookup audownload.windowsupdate.nsatc.net 

Each of those commands will return information about the hostname similar to this output:

Server:  modem.domain 
Address:  192.168.0.1 
  
Non-authoritative answer: 
Name:    sls.update.microsoft.com.nsatc.net 
Addresses:  2a01:111:f307:1790::f001:7a5 
          13.68.93.109 
Aliases:  sls.update.microsoft.com 

If you are being affected by a corrupted DNS entry from the DNS server on your network, it would be missing information like the addresses, for example, it might look like this:

Server:  modem.domain 
Address:  192.168.0.1
  
Non-authoritative answer: 
Name:    
Addresses:  
Aliases:  

ISPs or network administrators that maintain DNS servers for its clients, can mitigate this issue quickly for their customers by flushing the DNS records for the following Windows Update service hostnames:

sls.update.microsoft.com 
fe2.update.microsoft.com 
fe3.delivery.mp.microsoft.com 
au.download.windowsupdate.com 
sls.update.microsoft.com.nsatc.net 
fe2.update.microsoft.com.nsatc.net 
fe3.delivery.dsp.mp.microsoft.com.nsatc.net 
audownload.windowsupdate.nsatc.net 

That will unblock connections to the Windows Update service, so that updates can again start flowing through their networks again.

 If you are unable to contact your ISPs or network administrators, you may need to try other options such as:

• Connect your devices to other networks that are not affected
• Temporarily configure your device to use an alternate DNS provider until your network’s DNS entries are updated

Learn about the terminology that Microsoft uses to describe software updates