CDN endpoint - cannot set custom domain

Question

When I try to add custom domain to CDN endpoint, is says: "We couldn't find a DNS record for 'ogl.app' that points to 'oglapp.azureedge.net'. Before you can associate a domain with this CDN endpoint, you need to create a CNAME record with your DNS provider for 'ogl.app' that points to 'oglapp.azureedge.net'." But CNAME set properly. https://toolbox.googleapps.com/apps/dig/#CNAME/ What is wrong?

Answer 1

@60856927 ,

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

• Can you confirm if the CDN SKU is Microsoft? Or is it Azure CDN Standard from Edgio/ Azure CDN Premium from Edgio?
• Can you confirm if the CDN's endpoint is actually "oglapp.azureedge.net" and not something else?
• Can you share a screenshot of the error message please?

Cheers,

Kapil

Answer 2

When setting up a custom domain for your Azure Content Delivery Network (CDN) endpoint and encountering issues with DNS validation, there are several potential factors to consider. Here's a step-by-step guide to troubleshoot and resolve the issue:

Step-by-Step Troubleshooting

1. Verify CNAME Record
   • Use DNS lookup tools to verify that the CNAME record is correctly set up.
   • For example, using the Google Dig tool: Google Dig Tool
   • Ensure that the CNAME record for ogl.app points to oglapp.azureedge.net.

   
      CNAME record for ogl.app:
   
      ogl.app. IN CNAME oglapp.azureedge.net.
   
   

2. DNS Propagation
   • DNS changes can take some time to propagate. It might take up to 48 hours for DNS records to fully propagate across all DNS servers.
   • Use multiple DNS lookup tools to confirm the CNAME record:
     • DNS Checker
     • WhatsMyDNS
   • Check DNS propagation globally to ensure the CNAME record is available worldwide.
3. Cache and TTL (Time-To-Live)
   • Clear your DNS cache to ensure you're not seeing outdated DNS information.
   • You can clear the DNS cache on your local machine with the following commands:
     • Windows: ipconfig /flushdns
     • macOS: sudo dscacheutil -flushcache; sudo killall -HUP mDNSResponder
     • Linux: sudo systemd-resolve --flush-caches
   • Check the TTL value of your DNS record. If the TTL is high, it might take longer for changes to be recognized.
4. Correct DNS Configuration
   • Ensure that the CNAME record is correctly configured in your DNS provider's control panel.
   • Double-check for typos or incorrect values.
5. Custom Domain Validation in Azure
   • Navigate to the Azure portal: Azure Portal.
   • Go to your CDN profile and select the CDN endpoint.
   • Under the Custom domains section, try adding the custom domain again.
   • Azure will perform a DNS check to verify the CNAME record.
6. Check for DNSSEC
   • If your domain is using DNSSEC (DNS Security Extensions), ensure that it is configured correctly. DNSSEC misconfigurations can sometimes cause issues with DNS resolution.
7. Using Azure CLI for Validation
   • You can use Azure CLI to check the custom domain validation status. Run the following command:

   
      az cdn custom-domain validate --profile-name <CDN_Profile_Name> --endpoint-name <CDN_Endpoint_Name> --hostname ogl.app --resource-group <Resource_Group_Name>
   
   

   Replace <CDN_Profile_Name>, <CDN_Endpoint_Name>, and <Resource_Group_Name> with your actual resource names.

Example DNS Lookup Check

Using the Google Dig tool, you should see an output similar to this if the CNAME is correctly set:

; <<>> DiG 9.10.6 <<>> CNAME ogl.app

;; global options: +cmd

;; Got answer:

;; ->>HEADER<<- opcode: QUERY, status: NOERROR, id: 12345

;; flags: qr rd ra; QUERY: 1, ANSWER: 1, AUTHORITY: 2, ADDITIONAL: 1

;; QUESTION SECTION:

;ogl.app.                       IN      CNAME

;; ANSWER SECTION:

ogl.app.                3600    IN      CNAME   oglapp.azureedge.net.

;; AUTHORITY SECTION:

azureedge.net.          3600    IN      NS      ns1-azureedge.net.

azureedge.net.          3600    IN      NS      ns2-azureedge.net.

;; ADDITIONAL SECTION:

ns1-azureedge.net.      3600    IN      A       104.40.175.65

;; Query time: 100 msec

;; SERVER: 8.8.8.8#53(8.8.8.8)

;; WHEN: Thu Oct 14 12:34:56 UTC 2023

;; MSG SIZE  rcvd: 123

If you have followed all these steps and are still encountering issues, contacting Azure support for further assistance would be a prudent next step.