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The story in a nutshell

One day I show that one of my sub-domains marketing.kdktec.net is not working properly and when I visited the marketing.kdktec.net domain its show me the below in my Microsoft Edge web browser.

But this should be shown as the below;

So, what I do is open my Windows PowerShell and run the following commands using Windows PowerShell command “nslookup” to check the IP address of my sub-domain marketing.kdktec.net is pointing to.

PS C:\Users\admin> nslookup
> marketing.kdktec.net

Then it shows me this:

So, as you can see, this sub-domain marketing.kdktec.net is pointing to “104.21.78.84” through my “my.meraki.net” firewall DNS server at “10.11.41.1”

If you don’t know about the NSLOOKUP command in Windows PowerShell, Here is a summary of it.

NSLookup is a popular CMD utility commonly used to troubleshoot DNS issues. Remember, DNS is the phonebook of the internet. Instead of resolving people's names to phone numbers, DNS resolves a host or domain name to an IP address.

Then I had a doubt that this issue raising because of my Firewall server at my.meraki.net.

So, I have temporarily changed the DNS servers of my internet connection to Google DNS at 8.8.8.8 using the same NSLookup command feature as below;

PS C:\Users\admin> nslookup
Default Server: 
my.meraki.net
Address: 10.11.41.1

> server 8.8.8.8
Default Server: 
dns.google
Address: 8.8.8.8

> marketing.kdktec.net
Server: dns.google
Address: 8.8.8.8

Non-authoritative answer:
Name:   
marketing.kdktec.net
Address: 
104.21.78.84

Then it shows me the same result as I have done above with my Meraki firewall DNS server at “10.11.41.1”

So now it sure that the domain is pointing to an IP address that has no DNS data about my sub-domain marketing.kdktec.net

Common causes

1. A web request was sent to a Cloudflare IP address for a non-existent Cloudflare domain.

2. An external domain that is not using Cloudflare has a CNAME record to a domain active on Cloudflare

3. The target of the DNS CNAME record does not resolve.

4. A CNAME record in your Cloudflare DNS app requires resolution via a DNS provider that is currently offline.

5. Always Online is enabled for a Custom Hostname (SSL for SaaS) domain.

Resolution

A non-Cloudflare domain cannot CNAME to a Cloudflare domain unless the non-Cloudflare domain is added to a Cloudflare account.

Attempting to directly access DNS records used for Cloudflare CNAME setups also causes error 1001 For example www.example.com.cdn.cloudflare.net

So according to the 1st common cause mentioned above, I assume that the IP address I have set up for this sub-domain marketing.kdktec.net using my cPanel DNS zone editor “A Record” setting was wrong.

This sub-domain was pointed to IP address that provided by my bulk SMS and bulk voice SMS service provider before and it was worked properly. Now I’m assuming that somehow they have changed their server IP address.

So, what I do is contact them and submit my inquiries. Then what I found is that they have changed their service server IP from “104.21.78.84” to “158.69.106.51”

The solution to fix this DNS Resolution Error

So, what I do is log in to my cPanel and go to the “DNS Zone Editor” module under the “Domains” section as shown below screenshot;

Then I have gone to my sub-domain setting under DNS Zone Editor module using the “Manage” command under its primary domain DNS settings as shown in the below screenshot;

Then I have searched the sub-domain marketing.kdktec.net in the sub-domain list using the search option as shown in the below screenshot.

Then I have found the two sub-domains that relevant to marketing.kdktec.net in this DNS zone setting list as shown in the above screenshot.

Now what I have done is use the “Edit” button relevant to the above-mentioned sub-domains and edit the “A Record” as shown in the below screenshot.

Then I have tried to visit the sub-domain marketing.kdktec.net using my Microsoft Edge web browser as shown in the below screenshot.

As you can see now, my DNS resolution error 1001 has been resolved. So, I have done the same NSLookup check as before to conform my DNS zone configuration as shown in the below screenshot.

So now everything was fine and work well.

Conclusion

This kind of DNS resolution error 1001 message can be occurring due to a web request was sent to a Cloudflare IP address for a non-existent Cloudflare domain or any other points mentioned above under common causes and it can be solved by pointing the domain to the correct A record IP address using cPanel DNS zone editor module.

I hope you enjoyed how to post concerning DNS resolution error 1001 and please do not hesitate to leave your valuable comment concerning this article.

So until my next post, I wish you healthy and safe living during this Covid-19 pandemic time.

Thank you and best regards! K Dineh Kumara Founder, Director, and CEO KDKTEC and PC World Online Magazine