From the documentation
From the Oracle Golden Gate Installation and Setup Guide
"A range of ports for local Oracle GoldenGate communications: can be the default
range starting at port 7840 or a customized range of up to 256 other ports."
Therefore for default 7840 to 7840+256 (8096)
You can customize the range, but most folks stick with the default.
ok.any ports to be opened for cross communication between machine A and Machine B.?
Sorry just noticed you had a follow up,
Open the complete port range between the 2 machines 7840-8096
This has usually done the trick