Introduction Oracle Network Access Control List (ACL) controls which database users are allowed to make network connections from the Oracle Database to external hosts. In other words, it governs the outbound traffic leaving the database toward the outside world. It is commonly required when database PL/SQL packages such as UTL_SMTP , UTL_HTTP , and UTL_TCP need to access external network services. In this article, we will configure an Oracle Network ACL on Oracle Database 19c and use it to send an email through Gmail SMTP using UTL_SMTP . Gmail SMTP is used here purely to demonstrate the configuration end to end; the same steps apply to any SMTP server, so feel free to substitute your own SMTP host, port, and credentials. We will also configure an Oracle Wallet for TLS and use a Gmail App Password for authentication. The complete configuration will be demonstrated step by step, starting with the error received when no ACL is configured and ending with a successful email d...