* Question
What does the “IP Address” field in the VDS NetFlow configuration represent? Is it required to be a routable address?
* Answer
In the NetFlow configuration settings of a vSphere Distributed Switch (VDS), the “IP Address” field refers to the IP address used to identify the switch when exporting flow records to a collector. This field is not necessarily used for actual traffic routing. Instead, it serves primarily as an informational or logical identifier within the exported NetFlow or IPFIX records.
Key points:
Traffic Destination vs. Switch Identifier:
While the collector’s IP address and port determine where flow data is sent, the “IP Address” field in the VDS configuration identifies the source of the exported flows. It tells the NetFlow collector which virtual switch or ESXi host the data originated from.
Routability Not Required:
The address specified here does not need to be a valid or routable IP address on your network. It is used as a label within NetFlow packets. For example, 1.1.1.1 is a valid entry even if it does not correspond to an actual interface or reachable device.
Use Case for Logical IDs:
This allows flexibility in environments where hosts may not have unique external IPs or where administrators want to group flows under a consistent identifier, such as for multi-tenant environments or nested labs.
Collector Behavior:
How this field is interpreted or displayed depends on the capabilities of the NetFlow collector software (e.g., PRTG, SolarWinds, ManageEngine). Some collectors may display this IP as the source in dashboards or reports.
Example Scenario:
If multiple VDS switches are configured to export to the same NetFlow collector, assigning unique “IP Address” identifiers (e.g., 10.10.10.1, 10.10.10.2, etc.) helps the collector differentiate between data sources—even if those IPs aren’t routable.
Conclusion:
The “IP Address” in the VDS NetFlow configuration acts as a logical identifier for the source switch in exported flow records. It does not need to be routable, and may be set to any syntactically valid IP address suitable for your monitoring or organizational needs.
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