How do you refresh the configured DNS server for an App Service?

1
votes

I have an App Service that is connected to a VNET that has a VPN connection to our on-premises network. The VNET uses two of our on-premises DNS servers for resolving internal hostnames. I had to update one of the DNS IP addresses to point to a new server because it started getting flaky, but I'm not sure that the App Service has taken this change or not.

In the Kudu Console, the Environment Variables for the app service shows WEBSITE_DNS_ALT_SERVER = <TheOldBadIpAddress>. When I view the VNET integration settings in the portal, the correct DNS entry appears.

In order to get the environment variable to update, I've tried:

  • Restart the App Service
  • Disconnect / Reconnect the VNET integration in the portal.

Neither of these have any effect. How can I get my App Service to update its configured DNS servers?

1
azureazure-web-app-serviceazure-app-service-plans

1 Answers

1
votes

Neither of these have any effect. How can I get my App Service to update its configured DNS servers?

As Connect to Azure VNet mentioned about Managing the VNET Integrations as follows:

Along with the certificates we get the DNS configuration, routes and other similar things that describe the network. If those certificates or network information is changed then you will need to click "Sync Network".

NOTE: When you click "Sync Network" then you will cause a brief outage in connectivity between your app and your VNET. While your app will not be restarted the loss of connectivity could cause your site to not function properly.