🛡️ Packet Buffer Protection on Palo Alto Networks Firewalls

1. What is Packet Buffer Protection?

Packet Buffer Protection (PBP) is a feature designed to safeguard the firewall's packet buffers from single-session Denial-of-Service (DoS) attacks that can overwhelm the system and disrupt legitimate traffic. Unlike traditional DoS protection mechanisms that focus on new session rates, PBP monitors existing sessions and their impact on the firewall's packet buffer utilization.

By implementing PBP, the firewall can detect and mitigate sessions that consume excessive buffer resources, ensuring continued performance and availability.

Packet Buffer Protection Documentation

2. Configuring Packet Buffer Protection

PBP can be configured at both the global (device-wide) and per-zone levels. To effectively utilize PBP, follow these steps:

1. Enable Global Packet Buffer Protection:
   • Navigate to Device > Setup > Session and edit the Session Settings.
   • Check the Packet Buffer Protection option.
   • Configure the following thresholds:
     • Alert (%): Threshold for generating alert logs (default: 50%).
     • Activate (%): Threshold to start mitigation actions like Random Early Drop (RED) (default: 80%).
     • Block Hold Time (sec): Duration to wait before blocking offending sessions (default: 60 seconds).
     • Block Duration (sec): Duration to block the offending session or IP address (default: 3600 seconds).
   • Click OK and commit the changes.
2. Enable Per-Zone Packet Buffer Protection:
   • Navigate to Network > Zones and select the desired zone.
   • In the Zone Protection section, enable Packet Buffer Protection.
   • Click OK and commit the changes.

Configuring Packet Buffer Protection

3. Detecting Packet Buffer Exhaustion Issues

Monitoring packet buffer utilization is crucial to identify potential exhaustion issues. Use the following CLI commands to assess buffer usage:

• show running resource-monitor – Displays real-time resource utilization, including packet buffer statistics.
• show running resource-monitor ingress-backlogs – Provides insights into ingress buffer backlogs.
• debug dataplane pool statistics – Offers detailed information on dataplane buffer pools.

High buffer utilization (e.g., consistently above 90%) may indicate potential DoS attacks or misconfigurations leading to resource exhaustion.

Troubleshooting High Packet Buffer Usage

4. Best Practices

• Establish baseline buffer utilization metrics to set appropriate Alert and Activate thresholds.
• Regularly monitor system logs for alerts related to packet buffer utilization.
• Implement layered security by combining PBP with Zone Protection Profiles and DoS Protection Policies.
• Adjust Block Hold Time and Block Duration settings based on observed network behavior and threat patterns.

Packet Buffer Protection Best Practices