Azure WebApps custom domain - CNAME pointed to azurewebsite must exist?

Question

We are trying to migrate sites from AWS to Azure WebApps.

AS IS:

The CNAME of the existing site points to Imperva. Imperva then points to AWS Site.

TO BE:

The CNAME of the existing site points to Imperva. Imperva then points to Azure WebApp Site.

PROBLEM:

When I try to add the custom domain to azure Web Apps website, it complains with the error that the existing Site MUST have CNAME pointing to Azure Website.

see example below:

This means that as part of cutover, we need to do below: 1. Quicky update CNAME to point to azure web app 2. Once custom domain is setup in azure 3. Change the CNAME back to Imperva.

This sounds bit hacky.

Is above right approach or am I missing anything here?

Answer 1

The part that you're missing is the direction of the CNAME. What Azure wants to do is to ensure that you do actually have authority over that domain name. So they want you to create a CNAME that points from awverify.www.example.com to www.example.com

Once that record is created Azure will looking that record and ensure that it redirects to www.example.com. This has no impact on any existing configuration (unless you just happen to have awverify sub domain in uswe already!)

www.example.com will still work in exactly the same way as before until you are ready to move that name to Azure.