OPNsenseInterfaceOutputErrors #

Interface {{ $labels.interface }} ({{ $labels.device }}) has output errors

alert: OPNsenseInterfaceOutputErrors
annotations:
  description: |-
    Interface {{ $labels.interface }} ({{ $labels.device }}) has output errors
      VALUE = {{ $value }}
      LABELS = {{ $labels }}    
  runbook: https://srerun.github.io/prometheus-alerts/runbooks/opnsense/opnsenseinterfaceoutputerrors/
  summary: OPNsense interface output errors (instance {{ $labels.opnsense_instance
    }})
expr: increase(opnsense_interfaces_output_errors_total[5m]) > 0
for: 5m
labels:
  severity: warning

Meaning #

The OPNsenseInterfaceOutputErrors alert is triggered when the total number of output errors on an OPNsense interface increases within a 5-minute window. This alert indicates that there are issues with the interface’s ability to transmit data, which can lead to packet loss, delayed transmissions, and overall network performance degradation. The alert provides information about the specific interface, device, and instance experiencing the output errors, along with the current value and relevant labels.

Impact #

The impact of this alert can be significant, as output errors on an interface can affect the overall reliability and performance of the network. Some potential consequences include:

• Packet loss and corruption, leading to retransmissions and delayed data transfer
• Increased latency and jitter, affecting real-time applications and services
• Reduced network throughput, causing slower data transfer rates and decreased productivity
• Potential security risks, as faulty interfaces can be exploited by attackers

Diagnosis #

To diagnose the issue, follow these steps:

1. Identify the affected interface: Check the alert labels to determine which interface is experiencing output errors.
2. Verify interface configuration: Review the interface configuration to ensure it is set up correctly and matches the expected settings.
3. Check for hardware issues: Investigate if there are any hardware problems with the interface, such as faulty cables, connectors, or cards.
4. Analyze network traffic: Use tools like tcpdump or Wireshark to capture and analyze network traffic on the affected interface to identify any patterns or anomalies.
5. Consult OPNsense logs: Check the OPNsense system logs for any error messages or warnings related to the affected interface.

Mitigation #

To mitigate the issue, follow these steps:

1. Restart the affected interface: Try restarting the interface to see if it resolves the issue.
2. Update interface drivers: Ensure that the interface drivers are up-to-date, as outdated drivers can cause compatibility issues.
3. Replace faulty hardware: If hardware issues are identified, replace the faulty components to prevent further errors.
4. Optimize interface configuration: Review and optimize the interface configuration to ensure it is set up for optimal performance.
5. Monitor interface performance: Continuously monitor the interface performance to detect any future issues and take proactive measures to prevent them.