Azure App Service unable to resolve hostname of Virtual Machine on Vnet

Question

I have setup a virtual machine on a vnet to which an app service is connected to via vnet integration. The app service is able to connect to the virtual machine when using its private IP address, but unable to when using its hostname or FQDN. All services are using the Azure provided DNS.

How can I resolve the virtual machine via its hostname rather than relying on its (dynamic) private IP address?

Many thanks,
James

Answer 1

Hi @James Fleming

I believe you will need to configure the following for this to work:

"After your app integrates with your VNet, it uses the same DNS server that your VNet is configured with. By default, your app won't work with Azure DNS Private Zones. To work with Azure DNS Private Zones you need to add the following app settings:

WEBSITE_DNS_SERVER with value 168.63.129.16
WEBSITE_VNET_ROUTE_ALL with value 1
These settings will send all of your outbound calls from your app into your VNet in addition to enabling your app to use Azure DNS private zones."

https://learn.microsoft.com/en-us/azure/app-service/web-sites-integrate-with-vnet#azure-dns-private-zones

--I hope this helps. Please do not forget to "Accept the answer" and "Up-Vote" the answer or message(s) that helped you so that it can help others in the community looking for help on similar topics

Regards,
Didier3001