You require at least one static IP address for Service Processor (ILOM access). For the list of default ILOM IP addresses assigned to Exalogic machine hardware components at the time of manufacturing, see Default IP Addresses and Ports.
If you reconfigure these IP addresses during the initial configuration of the Exalogic machine using Oracle Exalogic Configuration Utility and its associated tools, you must use those IP addresses to access ILOM.
Note that as a general convention, root is used as the default user name.