// REFERENCE
Port 1521 (Oracle DB)
Protocol: TCP
Service: Oracle TNS
High risk
Oracle Database (TNS listener). Like any database, it must not be exposed: the listener allows enumerating SIDs and attacking credentials. Restrict it to the app network.
Related tools
Work with this in:
Related
1433
Port 1433 (MS SQL Server) 1434
Port 1434 (MS SQL Monitor) 2181
Port 2181 (ZooKeeper) 3306
Port 3306 (MySQL / MariaDB) 5432
Port 5432 (PostgreSQL) 5601
Port 5601 (Kibana)
Port 1433 (MS SQL Server) 1434
Port 1434 (MS SQL Monitor) 2181
Port 2181 (ZooKeeper) 3306
Port 3306 (MySQL / MariaDB) 5432
Port 5432 (PostgreSQL) 5601
Port 5601 (Kibana)
Assignments per the IANA port registry. Educational content.