restrict azure appservice / website to a domain
Azure Web App infrastructure uses different IP's for inbound and outbound communications. You have whitelisted the inbound IP address. Also, Whitelisting the domain name may not work either.
Azure Web Apps use a set of 4 outbound IP's for Outbound communication. This can be retrieved from portal:
- Select the web app
- Click on Properties
- Copy the OUTBOUND IP ADDRESSES
Whitelist these 4 IP Addresses the way you did earlier and then you could test by issuing a CURL request from the KUDU console (SCM) of the source app.
curl -i https://destinationsitename.azurewebsites.net