Health probe failure on Load Balancer in Azure

External Load Balancer reporting PA-VM instances as unhealthy because health probes going through PA-VM are failing, which results in traffic disruption because Load balancer not forwarding traffic to unhealthy instances.

• Review the Traffic logs for health probes traversing the firewall:

• Above details from traffic logs show there is no return traffic seen on the firewall.

• Platform: VM-Series Firewall
• PAN-OS / Plugin Version: 8.1.9 / -
• Deployment: Azure

• Traffic sent out of the firewall is not NAT’d correctly, so the return traffic is not re-directed back to the firewall interface

• Ensure that the NAT policy configured is performing both source (egress interface) and destination (internal resource IP) translations