When faced with this issue, you should take a close look at your DNS Server. The reason for this error is there is not a reverse Lookup Zone configured on the server or the reverse zone is crashed or does not have the right information. In this article, I will show you how to fix “Nslookup unknown: Fix cannot find non-existent domain”. Kindly refer to the following related guides: How to setup a cache-only DNS server, how to locate and edit the hosts file on Windows, how to install RSAT tools: DNS manager console missing from RSAT tools on Windows 10, and how to setup SPF and TXT Records in AWS.
In my case, I had a new connection because I changed my internet service provider, This made the records in DNS to be different from the new IP address assigned.
This is the sole reason why you are advised to configure a static address for your DNS server that will never change, or else you risk having DNS resolution errors.
Please see the following interesting articles: How to add and verify a custom domain name to Azure Active Directory. Active Directory: How to Setup a Domain Controller, and how to locate and edit the host file on macOS. Also, see How to know when an IP or domain has been blacklisted.
Reason for the Error “non-existent domain”
The DNS records are populated with the wrong IP parameters of my old network as shown below. We have to manually enter the right IPs’ to have this issue corrected.
Fix Nslookup unknown
To fix this issue you need to create or reconfigure the forward lookup zone and reverse lookup zone. Let’s start by correcting all the wrong entries associated with the forward lookup zone.
Forward lookup zones resolve names to IP addresses and Reverse lookup zones resolve IP addresses to names. Please see How to Fix “Unknown hard error” on Windows Server and Windows 10, How to set up a third-party DNS server on a Linux Server, and Domain Name System: How to create a DNS record.
Forwarders can be used on your DNS server to forward requests for which your DNS server does not have an authoritative answer.
Also, do the same for the Reverse lookup zone. As we can see from the image below, it has outdated IP parameters. Create a new zone first and delete the old zone records.
To create a new zone, follow the steps below. Go to the Reverse Zone Lookup folder icon, and right-click on it. Select New Zone
A new zone has now been created. You can now delete the outdated zone if you wish!
Next, create a new point record for your DNS server and other objects you have in your DNS. This is vital for IP address to domain name resolution.
Click on ok when complete.
After deleting the outdated reverse lookup zone, please restart your DNS server. This will apply the new changes.
Now, you have just the new zone you have created left and this is the desired result we want.
You can restart the DNS service or have the device restarted in order to apply the needed changes.
Now, the NSLookup unknown: cannot find a non-existent domain no longer exist. Please see How to fix Unknown Hard Error on Windows Server and Windows 10, and “NSlookup displays Error: Default Server is UnKnown – Reverse Lookup Zone“.
I hope you found this blog post helpful on how to fix Nslookup unknown: Fix cannot find non-existent domain. Please let me know in the comment session if you have any questions.