Azure web app with custom domains redirect non www to www

Question

While trying to finish the setup of our new website on an Azure web App (the app is an asp.net core 3.1 if that matter), I struggle to redirect the non-www url to our www url.

Right now, our www over https url works as expected. But using the non www url gives me the "Your connection is not private" page, which is kind of expected since the certificate is configured over the www address (I used an App Service Managed Certificate for that). At the same time, in the website in the Startup class, I have a custom rule made that should do the redirect. Yet, it seems from my understanding that the block I see is triggerred before the the code is executed on the website.

I tried all solutions defined on those forums for non www to www questions, for naked redirect as well. I will admit that before this project, I never had to configure dns record at all and I'm kind of lost as to what I could do to make it work there. I even tried to not enforce https on the web app as a way of not blocking the request.

As for url right now, I have the following (each with their status):

• https://mydomain.azurewebsites.net (working as expected)
• https://www.mydomain.com (working as expected)
• http://www.mydomain.com (redirected to https and working as expected)
• http://mydomain.com (redirect to https://mydomain.com as expected but expected the certificate from https://mydomain.azurewebsites.net which does not work)

I wonder at this point what I am missing.

Answer 1

@Yannick Vachon , Adding more info:

From the DNS configuration UI for your custom domain and follow the instructions at https://aka.ms/appservicecustomdns to configure a CNAME record for the hostname "www" and point it your web app's default domain name.
Kindly see the document 'configure-ssl-certificate' for more details.

App Service Managed Certificate (Preview) - It's a private certificate just to secure your www custom domain or any non-naked domain in App Service.

Kindly see the different between App Service Certificate and App Service Managed Certificate (here).

Hope this helps with some pointers. If you have further questions, please do share more details we will be more than happy to assist you.

Answer 2

Following your advice there, I bought a certificate from GoDaddy (using Azure portal to buy it). Took me let's say 20 minutes to fill the form, buy it, install everything and test it worked where I spent 20 hours trying to make the free certificate works without any success.

At some point, spending a small amount to not lose that much time is a correct answer :)