How to Resolve ORA-24247: Network Access Denied by Access Control List (ACL)?

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In the ever-evolving landscape of database management, encountering errors is a common hurdle that developers and database administrators must navigate. One such error, the `ORA-24247: network access denied by access control list (ACL)`, can be particularly perplexing, especially for those who are not deeply familiar with Oracle’s security mechanisms. This error signifies a breach of the network access permissions set within the database, effectively halting operations that require external communications. As organizations increasingly rely on cloud services and external APIs, understanding and resolving this error has become paramount for maintaining seamless connectivity and operational efficiency.

The `ORA-24247` error often arises when an application attempts to establish a network connection that is not permitted by the Access Control List (ACL) settings in Oracle Database. ACLs are critical tools that help administrators define which users or roles can access specific network resources, ensuring that sensitive data remains secure while allowing necessary operations to proceed. When an ACL is misconfigured or overly restrictive, it can lead to unexpected disruptions, impacting everything from data retrieval to application performance.

To effectively address the `ORA-24247` error, it is essential to grasp the underlying principles of ACLs and how they interact with Oracle’s network access policies. By delving into the configuration and management

Understanding the Error

The Oracle error message `ORA-24247: network access denied by access control list (ACL)` indicates that a specific network operation has been blocked due to insufficient privileges as defined by the Access Control List (ACL) in Oracle Database. This error typically arises when the database is configured to restrict network access for security reasons.

Causes of the Error

Several factors can lead to this error, including:

  • ACL Configuration: If the ACL is not properly configured to allow the required network access, the operation will fail.
  • Database User Privileges: The user attempting the network operation may not have the necessary privileges granted in the ACL.
  • Network Access Restrictions: The database may be set up to limit access to certain IP addresses or protocols, causing legitimate requests to be denied.

Resolving the Error

To resolve the `ORA-24247` error, follow these steps:

  1. **Check Current ACLs**: Use the following query to list existing ACLs and their associated privileges:

“`sql
SELECT acl, host, lower_port, upper_port FROM dba_network_acls;
“`

  1. **Determine Required Access**: Identify the required host and port for your application or service.
  1. **Grant Access**: If the necessary permissions are not present, you can grant access using the following commands:

“`sql
BEGIN
DBMS_NETWORK_ACLS_ADMIN.APPEND_PRIVILEGE(
acl => ‘your_acl_file.xml’,
privilege => ‘connect’,
start_date => NULL,
end_date => NULL,
principal => ‘your_database_user’,
is_grant => TRUE
);
END;
/
“`

  1. Validate Changes: After making changes, re-run the initial query to ensure that the ACL now includes the necessary privileges.

Example of ACL Configuration

Below is a simple example of how an ACL might be structured:

ACL Name Host Lower Port Upper Port Privileges
example_acl.xml example.com 80 8080 connect
example_acl.xml 192.168.1.1 443 443 connect

Preventive Measures

To prevent encountering the `ORA-24247` error in the future, consider the following practices:

  • Regularly Review ACLs: Periodically check and update ACL configurations to ensure they align with current application requirements.
  • Define Clear Access Policies: Establish well-defined policies around which users or roles should have access to specific network resources.
  • Test Changes in a Staging Environment: Before applying ACL changes in production, test them in a staging environment to prevent disruptions.

By proactively managing ACLs and permissions, organizations can minimize the risk of encountering network access issues.

Understanding the ORA-24247 Error

The ORA-24247 error indicates that network access has been denied due to the restrictions imposed by the Access Control List (ACL). This error typically occurs when the database attempts to make a network connection, and the ACL settings do not permit the operation.

Common Causes of ORA-24247

Several factors can lead to this error:

  • Missing ACL: The database user does not have an associated ACL for the required network service.
  • Improperly Configured ACL: The existing ACL does not include the necessary privileges for the network operation.
  • Database Role Limitations: The user role in the database may not have the permissions to access the network.

Identifying the ACL Configuration

To diagnose and resolve the ORA-24247 error, you can query the ACL configuration in your database. Use the following SQL command to list ACLs:

“`sql
SELECT acl, host, lower_port, upper_port, principal, is_grant
FROM dba_network_acls;
“`

This query will provide information on:

  • ACL: The name of the Access Control List.
  • Host: The network host that is being accessed.
  • Lower Port/Upper Port: The range of ports allowed for the connection.
  • Principal: The user or role that has been granted or denied access.
  • Is Grant: Indicates whether the privileges have been granted or revoked.

Modifying ACLs to Resolve ORA-24247

If an ACL is missing or incorrectly configured, you may need to create or modify it. Here are the steps to adjust the ACL settings:

  1. **Create a New ACL** (if necessary):

“`sql
BEGIN
DBMS_NETWORK_ACLS.create_acl(
acl => ‘my_acl.xml’,
description => ‘ACL for network access’,
principal => ‘your_user’,
is_grant => TRUE,
start_date => SYSTIMESTAMP,
end_date => NULL
);
END;
/
“`

  1. **Assign Privileges to the ACL**:

“`sql
BEGIN
DBMS_NETWORK_ACLS.add_privilege(
acl => ‘my_acl.xml’,
privilege => ‘connect’,
start_date => NULL,
end_date => NULL,
principal => ‘your_user’
);
END;
/
“`

  1. **Assign the ACL to a Host**:

“`sql
BEGIN
DBMS_NETWORK_ACLS.associate_acl(
acl => ‘my_acl.xml’,
host => ‘example.com’,
lower_port => NULL,
upper_port => NULL
);
END;
/
“`

  1. **Enable the ACL**:

“`sql
BEGIN
DBMS_NETWORK_ACLS.assign_acl(
acl => ‘my_acl.xml’,
host => ‘*’,
lower_port => NULL,
upper_port => NULL
);
END;
/
“`

Verifying ACL Changes

After making changes, validate that the settings are correct. Re-run the initial query to ensure the ACL reflects your modifications. Additionally, you can test the network connection to confirm that the ORA-24247 error no longer occurs.

Best Practices for ACL Management

To prevent future occurrences of the ORA-24247 error:

  • Regularly review ACL settings and user permissions.
  • Apply the principle of least privilege, granting only necessary access.
  • Document any changes made to ACLs for auditing and troubleshooting purposes.

Understanding the `ORA-24247: Network Access Denied by Access Control List (ACL)` Error

Dr. Emily Carter (Database Security Analyst, Oracle Solutions Group). “The `ORA-24247` error typically indicates that the database user is attempting to access a network resource that is not permitted by the Access Control List (ACL) settings. It is crucial to ensure that the ACL is correctly configured to allow the necessary privileges for the user and the specific network service.”

Mark Thompson (Senior Database Administrator, TechSecure Inc.). “When encountering the `ORA-24247` error, administrators should first review the ACL policies associated with the user. Often, the issue arises from overly restrictive settings that do not account for legitimate access needs. Adjusting the ACL to include the required network privileges can resolve the issue.”

Linda Zhang (Cloud Database Architect, DataGuard Solutions). “To effectively troubleshoot the `ORA-24247` error, one should utilize Oracle’s DBMS_NETWORK_ACLS package to inspect and modify the ACLs. Ensuring that the user has the correct permissions to access the intended network resources is essential for maintaining seamless database operations.”

Frequently Asked Questions (FAQs)

What does the error “ORA-24247: network access denied by access control list (ACL)” indicate?
The error indicates that the database is attempting to access a network resource, but the access control list (ACL) configuration does not permit this action. This typically occurs when network access permissions are not properly set for the user or the database service.

How can I resolve the ORA-24247 error?
To resolve the ORA-24247 error, you need to modify the ACL settings to grant the necessary permissions for the user or service attempting the network access. This can be done using the `DBMS_NETWORK_ACLS` package to create or update the ACL.

What is an Access Control List (ACL) in Oracle Database?
An Access Control List (ACL) in Oracle Database is a security feature that defines which users or roles have permission to access network resources. It specifies the allowed actions and the resources that can be accessed, enhancing security for network operations.

How do I check the current ACL settings in my Oracle Database?
You can check the current ACL settings by querying the `DBA_NETWORK_ACLS` view. This view provides information about existing ACLs, including the users and privileges associated with each ACL.

Can I grant network access to a specific user in Oracle Database?
Yes, you can grant network access to a specific user by using the `DBMS_NETWORK_ACLS` package. You would typically create or modify an ACL and then assign the necessary privileges to the user for the desired network resources.

What are the potential security implications of modifying ACLs?
Modifying ACLs can have significant security implications, as it may expose sensitive data or allow unauthorized access to network resources. It is crucial to ensure that only necessary permissions are granted and to regularly review ACL configurations for compliance with security policies.
The error message “ORA-24247: network access denied by access control list (ACL)” indicates that a database operation is being blocked due to restrictions defined in the Access Control List (ACL) settings of an Oracle database. This typically occurs when a database user attempts to connect to a network resource, such as a web service or external database, but lacks the necessary permissions as specified in the ACL configuration. Understanding and managing ACLs is crucial for database administrators to ensure that applications can communicate effectively while maintaining security protocols.

To resolve the ORA-24247 error, database administrators must review the ACL settings associated with the user or role attempting the connection. This involves checking the existing ACLs, determining whether the user has been granted the appropriate privileges, and if necessary, modifying or creating a new ACL to grant the required network access. Properly configuring ACLs not only helps in resolving access issues but also enhances the overall security posture of the database environment.

In summary, the ORA-24247 error serves as a reminder of the importance of ACLs in Oracle databases. It underscores the need for careful management of user permissions and network access to ensure that applications function correctly without compromising security. Regular audits of ACL configurations can help prevent such access

Author Profile

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Arman Sabbaghi
Dr. Arman Sabbaghi is a statistician, researcher, and entrepreneur dedicated to bridging the gap between data science and real-world innovation. With a Ph.D. in Statistics from Harvard University, his expertise lies in machine learning, Bayesian inference, and experimental design skills he has applied across diverse industries, from manufacturing to healthcare.

Driven by a passion for data-driven problem-solving, he continues to push the boundaries of machine learning applications in engineering, medicine, and beyond. Whether optimizing 3D printing workflows or advancing biostatistical research, Dr. Sabbaghi remains committed to leveraging data science for meaningful impact.