Prerequisites:

1. PRTG Installation: Ensure PRTG Network Monitor is installed and running in your environment.
2. Access to SSL/TLS Endpoints: You need access to the SSL/TLS endpoints (e.g., web servers, application servers) where wildcard SSL/TLS certificates are deployed.
3. Administrator Access: Obtain administrative access to configure sensors and settings in PRTG.

Setting Up SSL/TLS Certificate Monitoring:

1. Add SSL/TLS Endpoint(s): In PRTG, navigate to "Devices" and add the SSL/TLS endpoint(s) you want to monitor.
2. Install SSL/TLS Certificate Sensor: Click on the SSL/TLS endpoint device you added, then go to "Add Sensor" > "By Type" > Select "SSL Certificate Sensor."
3. Configure Sensor Parameters: Define the parameters for monitoring, including the hostname or IP address of the SSL/TLS endpoint, port number, and monitoring intervals.
4. Select Monitoring Metrics: Choose the monitoring metrics you want to track, such as certificate subject alternative names (SANs), wildcard usage, expiration date, and certificate issuer.
5. Test Configuration: Verify that the sensors can successfully retrieve SSL/TLS certificate information and monitor wildcard usage.

Monitoring SSL/TLS Certificate Wildcard Usage:

1. Real-time Monitoring: Access the PRTG dashboard to view real-time updates on SSL/TLS certificate wildcard usage.
2. Wildcard Domain Matching: Monitor SSL/TLS certificate subject alternative names (SANs) to identify wildcard entries (e.g., *.example.com) used for securing multiple subdomains under a single certificate.
3. Wildcard Certificate Status: Track the status of wildcard SSL/TLS certificates to ensure they are valid, trusted, and correctly configured for wildcard domain matching.
4. Wildcard Renewal and Expiration: Monitor SSL/TLS certificate expiration dates and renewal status to ensure timely renewal of wildcard certificates and prevent service disruptions or security vulnerabilities.
5. Threshold-based Alerts: Set up threshold-based alerts to notify administrators when wildcard SSL/TLS certificates approach expiration, when wildcard usage patterns change, or when anomalies are detected, indicating potential misconfigurations or security risks.

Best Practices:

1. Wildcard Certificate Management: Implement robust wildcard certificate management practices, including regular renewal, certificate revocation procedures, and monitoring wildcard usage to prevent unauthorized wildcard certificate issuance.
2. Domain Coverage: Ensure wildcard SSL/TLS certificates cover only the necessary subdomains within the organization's domain space to minimize the risk of unauthorized domain usage and prevent wildcard abuse.
3. Certificate Transparency: Enable certificate transparency monitoring to detect any unauthorized or unexpected wildcard certificate issuance and ensure compliance with industry standards and best practices.
4. Certificate Authority (CA) Verification: Verify that wildcard SSL/TLS certificates are issued by reputable and trusted certificate authorities (CAs) and that wildcard domain ownership is validated according to CA/Browser Forum guidelines.
5. Wildcard Certificate Rotation: Implement certificate rotation policies to periodically rotate wildcard SSL/TLS certificates and cryptographic keys to mitigate the risk of certificate compromise and improve overall security posture.

Troubleshooting:

1. Connection Issues: Ensure that PRTG can establish HTTPS connections to the SSL/TLS endpoints and retrieve certificate information successfully.
2. Sensor Configuration: Double-check sensor settings, including hostname or IP address, port number, and monitoring intervals, and verify that the correct sensor type is used for monitoring SSL/TLS certificates.
3. Certificate Inspection: Review wildcard SSL/TLS certificate details, including SANs, expiration dates, and issuer information, to troubleshoot issues related to wildcard usage or certificate misconfigurations.
4. Certificate Revocation Checking: Verify that wildcard SSL/TLS certificates are properly revoked if they are no longer needed or if they are compromised to prevent unauthorized wildcard usage and maintain the trustworthiness of SSL/TLS communications.
5. Domain Validation: Validate wildcard domain ownership and control to ensure that wildcard SSL/TLS certificates are issued only for authorized domains and prevent potential abuse or misuse of wildcard certificates for unauthorized subdomains.

By leveraging PRTG Network Monitor to monitor SSL/TLS certificate wildcard usage, you can enhance the security and integrity of encrypted communications, mitigate security risks, and maintain compliance with industry standards and best practices. Real-time monitoring, proactive alerting, and comprehensive analysis enable you to detect and address wildcard certificate issues promptly, strengthen cryptographic defenses, and safeguard sensitive data transmitted over the network. With PRTG, you can effectively manage and monitor SSL/TLS certificate wildcard usage to meet the operational requirements and security goals of your organization.