> Source: [sk178564](https://support.checkpoint.com/results/sk/sk178564)

# sk178564 - TCPDUMP on Azure Gateway external interface does not show Health Probe traffic

| Property | Value |
|----------|-------|
| Solution ID | sk178564 |
| Date Created | 2022-04-04 |
| Last Modified | 2026-05-11 |
| Technical Level | General |
| Products | Cloud Firewall |
| Versions | R82.10, R81.20, R82 |
| OS | Gaia |
| Platform | Azure |

## Symptoms

- * TCPDUMP on Azure Gateway external interface does not show Health Probe traffic.

* TCPDUMP on the Gateway's internal interface does show Health Probe traffic.

## Cause

External Load Balancer Health Probe Check for Instances:

A packet matching your deployment's front end and rule is generated periodically. It traverses the region from the source to the host, where there is a VM in the back-end pool. The load balancer infrastructure performs the same load balancing and translation operations as it does for all other traffic. This probe is in-band on your load-balanced endpoint. After the probe arrives on the compute host, where there is a healthy VM in the back-end pool, the compute host generates a response to the probing service. Your VM does not see this traffic.

Internal Load Balancer Health Probe Check for Instances:

The health probe status metric describes the health of your application deployment as configured by you when you configure the health probe of your load balancer. The load balancer uses the status of the health probe to determine where to send new flows. Health probes source is an Azure infrastructure address, and you can see it in the guest OS of the VM.

For more information refer to:   
<https://docs.microsoft.com/en-us/azure/load-balancer/load-balancer-standard-diagnostics>

## Solution

No fix is required. This behavior is by design.

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