The IPv4 IP address of the endpoint on which you want Amazon Route 53 to perform health checks. If you don't specify a value for IPAddress, Amazon Route 53 sends a DNS request to resolve the domain name that you specify in FullyQualifiedDomainName at the interval you specify in RequestInterval. Using an IP address that DNS returns, Amazon Route 53 then checks the health of the endpoint.
f the endpoint is an Amazon EC2 instance, we recommend that you create an Elastic IP address, associate it with your Amazon EC2 instance, and specify the Elastic IP address for IPAddress. This ensures that the IP address of your instance never changes. For more information, see Elastic IP Addresses (EIP) (http://docs.aws.amazon.com/AWSEC2/latest/UserGuide/elastic-ip-addresses-eip.html) in the Amazon EC2 User Guide for Linux Instances.
If a health check already has a value for IPAddress, you can change the
value. However, you can't update an existing health check to add or remove the value of IPAddress.
For more information, see UpdateHealthCheckRequest$FullyQualifiedDomainName.