After you’ve added custom domains to your Cloud Platform application, you must update the DNS records for those domains with your DNS provider before your website can serve content to visitors.
You can view the recommended DNS settings for a selected environment on the Domains page. If the Domains page displays a CNAME, configure all custom domains on the environment with the CNAME record (including bare domains if supported by your DNS provider). If the DNS Information section doesn’t display a CNAME, or if your DNS provider doesn’t support CNAME records for bare domains, configure any A record entries for your domains to all listed public IP addresses.
For example, if your application’s bare domain name is example.com and your public IP addresses are 123.123.123.123 and 123.123.123.124, you must configure two A record entries for example.com; one for 123.123.123.123 and another for 123.123.123.124.
Custom domains should not be pointed to any endpoints that are not listed in the DNS section of the Domains page, as this can cause unpredictable results or even downtime during platform maintenance events.
Changes to DNS records
If you have an existing application and decide to upgrade to Shield, both your DNS records and any EIPs assigned to your application infrastructure will change. IP addresses can’t move into or out of a virtual private cloud (VPC).
As a result, when you configure your application in Shield, you must point the DNS records of your application to the new IP address in the VPC. For more information, see Shield.