Here’s a quick overview of the steps you need to take to put Front Door in front of an Azure Web App. In this case, the web app runs a WordPress site.
Step 1: DNS
Suppose you deployed the Web App and its name is gebawptest.azurewebsites.net and you want to reach the site via wp.baeke.info. Traffic will flow like this:
user types wp.baeke.info ---CNAME to xyz.azurefd.net--> Front Door --- connects to gebawptest.azurewebsites.net using wp.baeke.info host header
It’s clear that later, in Front Door, you will have to specify the host header (wp.baeke.info in this case). More on that later…
If you have worked with Azure Web App before, you probably know you need to configure the host header sent by the browser as a custom domain on the web app. Something like this:
In this case, we do not want to resolve wp.baeke.info to the web app but to Front Door. To make the custom domain assignment work (because the web app will verify the custom name), add the following TXT record to DNS:
TXT awverify.wp gebawptest.azurewebsites.net
For example in CloudFlare:
With the above TXT record, I could easily add wp.baeke.info as a custom domain to the gebawptest.azurewebsites.net web app.
Note: wp.baeke.info is a CNAME to your Front Door domain (see below)
Step 2: Front Door
My Front Door designer looks like this:
When you create a Front Door, you need to give it a name. In my case that is gebafd.azurefd.net. With wp.baeke.info as a CNAME for gebafd.azurefd.net, you can easily add wp.baeke.info as an additional Frontend host.
The backend pool is the Azure Web App. It’s configured as follows:
You should connect to the web app using its original name but send wp.baeke.info as the host header. This allows Front Door to connect to the web app correctly.
The last part of the Front Door config is a simple rule that connects the frontend wp.baeke.info to the backend pool using HTTP only.
Step 3: WordPress config
With the default Azure WordPress templates, you do not need to modify anything because wp-config.php contains the following settings:
define('WP_SITEURL', 'http://' . $_SERVER['HTTP_HOST'] . '/'); define('WP_HOME', 'http://' . $_SERVER['HTTP_HOST'] . '/');
If you want, you can change this to:
define('WP_SITEURL', 'http://wp.baeke.info/' ); define('WP_HOME', 'http://wp.baeke.info/');
Step 4: Blocking access from other locations
In general, you want users to only connect to the site via Front Door. To achieve this, add the following access restrictions to the Web App: