The Informatica domain is the fundamental administrative unit for services, users, and resources. A node is the logical representation of a single machine. A domain contains one or more nodes.
If you are installing on multiple machines, you can create multiple domains. If you create a domain, the node on the machine where you install becomes a gateway node in the domain. You can select the Enable Secure Communication option to set up secure communication between services within the domain.
When you install the Informatica services, you create a node on the machine. You can create a domain and add the node to the domain. If you do not create a domain, you can join the node to another domain.
If you join a domain, you can configure the node that you create to be a gateway node. When you create a gateway node, you can select enable a secure HTTPS connection to Informatica Administrator.