These are the default ports which should be open for OEM12c to work properly
Enterprise Manager Upload Http Port=4889
Enterprise Manager Upload Http SSL Port=4900
Enterprise Manager Central Console Http SSL Port=7799
Node Manager Http SSL Port=7403
Managed Server Http Port=7202
Enterprise Manager Central Console Http Port=7788
Oracle Management Agent Port=3872
Admin Server Http SSL Port=7101
Managed Server Http SSL Port=7301
