I have a Wordpress site on Azure App Services. The setup automatically created a CDN endpoint. Should I point my custom domain to the IP address of the Web app, or use a CNAME and point it to the CDN endpoint?

@massad Thank you for reaching out. You will have to use a CNAME and point it to the CDN endpoint as described here . The custom domain should resolve to Azure CDN endpoint, as it will provide cached response to the clients and will have less latency. The CDN endpoint will serve the data from its origin (Web App) to provide any un-cached response. Hope this helps! Please let me know if you have any additional questions. Thank you! Please "Accept the answer" if the information helped you. This will help us and others in the community as well.

Custom Domains in Azure App Services Wordpress Web App: Point to App or to CDN

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ChaitanyaNaykodi-MSFT 26,216 Reputation points Microsoft Employee

2023-10-17T00:13:24.8633333+00:00

@massad

Thank you for reaching out.

You will have to use a CNAME and point it to the CDN endpoint as described here.

The custom domain should resolve to Azure CDN endpoint, as it will provide cached response to the clients and will have less latency. The CDN endpoint will serve the data from its origin (Web App) to provide any un-cached response.

Hope this helps! Please let me know if you have any additional questions. Thank you!

Please "Accept the answer" if the information helped you. This will help us and others in the community as well.
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massad 65 Reputation points

2023-10-17T01:08:35.51+00:00

The issue with this is you can't use the root domain. This still has to point to an IP address.

Assuming we use the CNAME for www and point it to the edge URL - Do you recommend:

Not pointing the root domain to any IP

Pointing the root domain to the web app IP

If we are using www and no IP, what happens when you access the root domain?

If we are using www and the root domain pointing to an IP, how do search engines know which one to use (or does it matter)?

Thanks!

ChaitanyaNaykodi-MSFT 26,216 Reputation points Microsoft Employee

2023-10-17T01:59:06.8066667+00:00

@34801893

Thank you for getting back.

In this case you can Onboard a root or apex domain to an existing Azure CDN endpoint as described here

You can't map your apex domain to an IP address if your intent is to onboard it to Azure CDN. The DNS protocol prevents the assignment of CNAME records at the zone apex. For example, if your domain is contoso.com; you can create CNAME records for somelabel.contoso.com; but you can't create a CNAME for contoso.com itself. This restriction presents a problem for application owners who have load-balanced applications behind Azure CDN. Since using a CDN profile requires creation of a CNAME record, it isn't possible to point at the CDN profile from the zone apex. This problem can be resolved by using alias records in Azure DNS. Unlike CNAME records, alias records are created at the zone apex. Application owners can use it to point their zone apex record to a CDN profile that has public endpoints. Application owners point to the same CDN profile that's used for any other domain within their DNS zone. For example, contoso.com and www.contoso.com can point to the same CDN profile. Mapping your apex or root domain to your CDN profile requires CNAME flattening or DNS chasing. A mechanism where the DNS provider recursively resolves the CNAME entry until it hits an IP address. This functionality is supported with Azure DNS for CDN endpoints.

Hope this helps! Please let me know if you have any additional questions. Thank you!

Please "Accept the answer" if the information helped you. This will help us and others in the community as well.

massad 65 Reputation points

2023-10-17T18:30:02.6366667+00:00

FYI - I tried CNAME flattening on my root domain in CloudFlare so that I could add the root domain as a custom domain for the CDN, but the CDN doesn't recognize it. It keeps denying the domain add with a message about adding a CNAME. I will try the Azure DNS method described in the docs.

ChaitanyaNaykodi-MSFT 26,216 Reputation points Microsoft Employee

2023-10-17T18:41:02.63+00:00

@34801893

Thank you for getting back. Yes, please let us know if you are facing issue with Azure DNS method.

massad 65 Reputation points

2023-10-19T15:37:52.3533333+00:00

This doesn't seem to work properly. When I set the www of my custom domain to the CDN Endpoint using a CNAME, it works for the home page, but other links on my site are reverting to the <site-name>.azurewebsites.net domain. There is no option to set a domain as Default on the Web App Domains blade, so not sure what else to do.

massad 65 Reputation points

2023-10-19T15:40:21.09+00:00

Also - this is still with Cloudflare. I want to make sure it works with www on Cloudflare first before moving to Azure DNS because Azure DNS has a fee.

ChaitanyaNaykodi-MSFT 26,216 Reputation points Microsoft Employee

2023-10-19T23:53:10.76+00:00

@34801893

Thank you for getting back.

CNAME flattening should recursively resolve to an IP address. I think it could help if you can involve Cloudflare support in this case.

Additional referance:

https://blog.cloudflare.com/introducing-cname-flattening-rfc-compliant-cnames-at-a-domains-root/

massad 65 Reputation points

2023-10-20T00:05:27.81+00:00

The CNAME is not the problem for www. You can’t even add a custom domain to the endpoint unless the CNAME is set up correctly. But even with the DNS set up correctly it does this. Actually you can use the endpoint url directly to access the app and then see in the navigation that the links are pointing to <site-name>.azurewebsites.net instead of the endpoint domain or the www custom domain.
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Custom Domains in Azure App Services Wordpress Web App: Point to App or to CDN

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