The following figure illustrates a rough overview of the network structure of a public-cloud instance. Usually, the client is hidden behind a firewall and proxy, which can be established by a company or at home within the private network. All cloud instances have two IP addresses: a private one, which is only visible in the cloud network itself and a public IP, which is visible on the Internet. The latter is normally not published in the runtime environment of the cloud instance itself, which is commonly called Network Address Translation (NAT). Moreover, the public IP address is not fixed, it changes every time the instance is started or rebooted.
The changing public IP address of the cloud instance may cause trouble during the configuration of software applications. There are two way of avoiding this:
Provide an easy-to-use script or software that automatically configures the application correctly using the new IP address. Depending on the application, this approach may not be necessary. However, it is always associated with the need to reconfigure the client's user access to that system because the URL for the applications changes with the IP address.
Use another service provided by Amazon called "elastic IP". This is a kind of static IP address provided by Amazon. You can choose from a bundle of IP addresses associated with your Amazon account and then assign the IP address you selected to your cloud instance every time you have to start or reboot it. This service is not free as the IP addresses have to be reserved for your account. It is payable in addition to any other service costs your instance incurs. For the installation of PPM, an "elastic IP" is required.