When the source database and target database reside on different servers, you must open the ports that are used by Oracle GoldenGate. You need one port for Oracle GoldenGate Manager plus one port for each process you run.
For Zero Downtime, you run Oracle GoldenGate Manager and five processes in each environment. Therefore, you need six open ports on the active environment and six open ports on the passive environment. By default, the Oracle GoldenGate port range is 7809-7820.
For information about specifying ports for remote network communications, see the following topics in the
Oracle® GoldenGate Administering Oracle GoldenGate for Windows and UNIX