DNS Problems & Domain Redirections

Question

Hello everyone, we're facing a significant issue.

Periodically, we encounter the following error messages: DNS_PROBE_FINISHED_NXDOMAIN, as well as "name not resolved."

After 30 minutes to 1 hour, it returns to normal, only to repeat randomly throughout the day (sometimes not at all, sometimes 1-3 times per day). So, the question is, what's causing the problem with our domain delegation to Azure?

We're correctly sending A, TXT, NS, and other records. Additionally, we've included a wildcard entry (*.mydomain) as per the standard procedure for delegating a domain and subdomains to Microsoft Azure.

On the Azure side, we've added several subdomains as well as the primary domain to enable SSL certification for subdomains. Furthermore, we've set the main site via WordPress to mydomain.com.

That's the first problem.

The second issue arises when clients sometimes access the site using *.mydomain.com.

Our AJAX requests are consistently failing because the domain is not mydomain.com but *.mydomain.com. We're attempting to implement a basic redirection to our primary domain.

Overall our desired outcome should be to redirect *.mydomain.azurewebsites.net and *.mydomain.com both to mydomain.com. How can we achieve this? We've tried several methods, but none have worked as intended. We've also reached out to Microsoft Support (Premium), but we're still awaiting a response from their side.

Cheers

Answer 1

Hi @Neleron

Welcome to the Microsoft Q&A Platform. Thank you for reaching out & I hope you are doing well.

I understand that you are facing issues with your subdomain redirection. Following up on the error messages: DNS_PROBE_FINISHED_NXDOMAIN, as well as "name not resolved." I suspect below could be the probable causes of the issue.

• Problem with DNS server: The DNS server you're using might be experiencing issues or may not be responding.
• Blocked by firewall or antivirus: Sometimes, firewall or antivirus settings may block certain domains or interfere with DNS resolution.
• Incorrect DNS settings: Your DNS (Domain Name System) settings might be misconfigured.
• DNS cache: Your DNS cache might be corrupted, causing the Machine to fail in resolving the domain.

Just to validate your configuration kindly confirm if this is how you setup your delegation domain *.mydomain.com on Azure Public DNS.

Set up DNS Zone in Azure:

• Log in to the Azure Portal.
• Navigate to "Create a resource" and search for "DNS Zone."
• Create a new DNS Zone for your subdomain (e.g., *.mydomain.com).
• Note down the name servers provided by Azure for this DNS zone.
• Update DNS Records in Root Domain Provider:
• Log in to your root domain provider account (e.g., WordPress).
• Go to the DNS management section for your root domain (mydomain.com).
• Add a new NS (Name Server) record for your subdomain (*.mydomain.com).
• Set the value of this NS record to the name servers provided by Azure for your DNS zone.
• Save the changes.
• Verify Configuration:
• Wait for DNS propagation to complete, which can take up to 24-48 hours.
• Use online DNS lookup tools or commands like nslookup or dig to verify that the NS records for your subdomain are pointing to Azure's name servers.

nslookup -type=NS *.mydomain.com (If testing on Windows Machine)
dig NS *.mydomain.com (If testing on Linux Machine)
 

• Configure DNS Records in Azure DNS:
• Once the delegation is set up, you can manage the DNS records for your subdomain in Azure DNS.
• Add necessary records like A, CNAME, MX, TXT, etc., for your subdomain within the Azure DNS zone according to your requirements.

Troubleshooting

• I assume the above configuration steps were followed and even during the issue times *.mydomain.com ns records show Azure name servers. If it does not follow up with your root domain provider (e.g. WordPress).
• If however, it still shows Azure name servers and resolutions still fail, check your Firewall logs if you see any DNS traffic dropped On Firewall or if you any DNS traffic at all for Azure name servers on your Firewall.
• Run DNS trace and compare the output during the issue time and when dns resolution working normally. Kindly share your observations.

dig +trace *.mydomain.com.

I however did not understand your second query, can you kindly elaborate it further.

Regards

Ujjawal Tyagi