Port 1521: Oracle
Port 1521 is the Oracle database listener, where clients connect to an Oracle instance. It is a common target, so restrict it to trusted application hosts.
TCPDatabasesUnencrypted by defaultIANA assigned
| Port number | 1521 |
|---|---|
| Service | Oracle database listener |
| Protocol | TCP |
| Category | Databases |
| Default encryption | No |
Security note. Port 1521 is not encrypted by default. Restrict it to trusted networks, or use an encrypted alternative where one exists, to avoid exposing credentials and data in transit.
Frequently asked questions
What is port 1521 used for?
Port 1521 is the Oracle database listener, where clients connect to an Oracle instance. It is a common target, so restrict it to trusted application hosts.
Is port 1521 TCP or UDP?
Port 1521 (Oracle) uses TCP.
Is port 1521 secure?
Port 1521 is not encrypted by default. Where possible, use an encrypted alternative or tunnel it over TLS or a VPN.
Should I open port 1521 on my firewall?
Only if you specifically need Oracle. Expose it to the smallest set of trusted sources, and never open database or Windows-service ports to the whole internet.