iSM: Low Metric Assigned to iDRAC USB NIC Conflicts with IPv4 Resolution or Cluster Heartbeat

Summary: Domain Name System (DNS) resolving the local hostname may return the internal IP address of the USB Network Interface Card (NIC) passthrough device enabled by iDRAC Service Module (iSM). This can cause issues with internal network devices configured with 169.254.x.x nonroutable addresses. The metric of the USB NIC device should be manually set to a high number so that internal network devices take precedence. ...

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Symptoms

Some third-party products and services rely on resolving the host’s local DNS name to the fastest network interface in the host. Windows determines this order by automatically assigning metric values based on the interface’s rated speed when determining the route table.

If the OS Passthrough feature of iDRAC is enabled, the USB NIC presented may be assigned an equal or lower (faster) value than other NICs. This can result in nslookup resolving the host with the USB NIC’s internal 169.254.x.x address.

To see what Windows chooses for the InterfaceMetric values for all interfaces including the USB NIC, use PowerShell:

Get-NetIPInterface | sort InterfaceMetric

Cause

iDRAC Service Module attempts to assign metrics to the USB NIC network device that only communicates internally with iDRAC. It may take precedence over internal devices with a lower metric.

Resolution

This does not cause issues with various internal Windows services but has been found to cause issues with certain third-party services such as web proxy servers that expect a routable address. Conflicts have also been seen with NICs also assigned 169.254.x.x addresses with higher (slower) metrics used for clustering heartbeats.

Engineering recommends overriding the automatic USB NIC metric with a higher value such as 999. This can be done with the Windows user interface by opening the USB NIC interface’s IPv4 properties then clicking Advanced > IP Settings and clear Automatic metric before entering 999. Alternately, this can be done using PowerShell with the command:

Set-NetIPInterface -ifindex <interface #> -InterfaceMetric 999

iDRAC Service Module (iSM) must enable this USB NIC interface and it still works correctly with the higher (slower) metric with no performance concerns.

Affected Products

iDRAC9 - 4.xx Series, Storage Spaces Direct R440 Ready Node, Storage Spaces Direct R640 Ready Node, Storage Spaces Direct R740xd Ready Node, Storage Spaces Direct R740xd2 Ready node, OEMR R240, OEMR R250, OEMR XE R250, OEMR R260, OEMR XE R260 , OEMR R340, OEMR R350, OEMR XE R350, OEMR R360, OEMR XE R360, OEMR R440, PowerEdge XR2, OEMR R450, OEMR R540, OEMR R550, OEMR R5500, OEMR R640, OEMR XL R640, OEMR R6415, OEMR R650, OEMR R650xs, OEMR R6515, OEMR R6525, OEMR R660, OEMR XL R660, OEMR R660xs, OEMR R6615, OEMR R6625, OEMR R740, OEMR XL R740, OEMR R740xd, OEMR XL R740xd, OEMR R740xd2, OEMR R7415, OEMR R7425, OEMR R750, OEMR R750xa, OEMR R750xs, OEMR R7515, OEMR R7525, OEMR R760, OEMR R760xa, OEMR R760XD2, OEMR XL R760, OEMR R760xs, OEMR R7615, OEMR R7625, OEMR R840, OEMR R860, OEMR R940, OEMR R940xa, OEMR R960, OEMR T140, OEMR T150, OEMR T340, OEMR T350, OEMR T360, OEMR T440, OEMR T550, OEMR T560, OEMR T640, OEMR XL T640, OEMR XL R240, OEMR XL R340, OEMR XL R660xs, OEMR XL R6615, OEMR XL R6625, OEMR XL R760xs, OEMR XL R7615, OEMR XL R7625, OEMR XR11, OEMR XR12, OEMR XR4510c, OEMR XR4520c, OEMR XR5610, OEMR XR7620, OEMR XR8610t, OEMR XR8620t, PowerEdge FC640, PowerEdge M640, PowerEdge M640 (for PE VRTX), PowerEdge MX740C, PowerEdge MX750c, PowerEdge MX760c, PowerEdge MX840C, PowerEdge R240, PowerEdge R250, PowerEdge R260, PowerEdge R340, PowerEdge R350, PowerEdge R360, PowerEdge R440, PowerEdge R450, PowerEdge R540, PowerEdge R550, PowerEdge R640, PowerEdge R6415, PowerEdge R650, PowerEdge R650xs, PowerEdge R6515, PowerEdge R6525, PowerEdge R660, PowerEdge R660xs, PowerEdge R6615, PowerEdge R6625, PowerEdge R740, PowerEdge R740XD, PowerEdge R740XD2, PowerEdge R7415, PowerEdge R7425, PowerEdge R750, PowerEdge R750XA, PowerEdge R750xs, PowerEdge R7515, PowerEdge R7525, PowerEdge R760, PowerEdge R760XA, PowerEdge R760xd2, PowerEdge R760xs, PowerEdge R7615, PowerEdge R7625, PowerEdge R840, PowerEdge R860, PowerEdge R940, PowerEdge R940xa, PowerEdge R960, PowerEdge T140, PowerEdge T150, PowerEdge T160, PowerEdge T340, PowerEdge T350, PowerEdge T360, PowerEdge T440, PowerEdge T550, PowerEdge T560, PowerEdge T640, PowerEdge XE2420, PowerEdge XE7100, PowerEdge XE7420, PowerEdge XE7440, PowerEdge XE8545, PowerEdge XE8640, PowerEdge XE9640, PowerEdge XE9680, PowerEdge XR11, PowerEdge XR12, PowerEdge XR4510c, PowerEdge XR4520c, PowerEdge XR5610, PowerEdge XR7620, PowerEdge XR8610t, PowerEdge XR8620t, PowerFlex appliance R650, PowerFlex appliance R6525, PowerFlex appliance R660, PowerFlex appliance R6625, Powerflex appliance R750, PowerFlex appliance R760, PowerFlex appliance R7625, PowerFlex custom node R650, PowerFlex custom node R6525, PowerFlex custom node R660, PowerFlex custom node R6625, PowerFlex custom node R750, PowerFlex custom node R760, PowerFlex custom node R7625, PowerFlex custom node R860, VxFlex Ready Node R640, VxFlex Ready Node R740xd, Dell EMC vSAN C6420 Ready Node, Dell EMC vSAN MX740c Ready Node, Dell EMC vSAN MX750c Ready Node, Dell vSAN Ready Node MX760c, Dell EMC vSAN R440 Ready Node, Dell EMC vSAN R640 Ready Node, Dell EMC vSAN R6415 Ready Node, Dell EMC vSAN R650 Ready Node, Dell EMC vSAN R6515 Ready Node, vSAN Ready Node R660, Dell vSAN R6615 Ready Node, Dell EMC vSAN R740 Ready Node, Dell EMC vSAN R740xd Ready Node, Dell EMC vSAN R750 Ready Node, Dell EMC vSAN R7515 Ready Node, Dell EMC vSAN R760 Ready Node, Dell vSAN R7615 Ready Node, Dell vSAN Ready Node R7625, Dell EMC vSAN R840 Ready Node, Dell EMC vSAN T350 Ready Node, PowerFlex appliance R740XD, PowerFlex appliance R7525, PowerFlex appliance R840, VxFlex Ready Node R840 ...

Products

iDRAC Service Module, iDRAC Service Module 4.x, iDRAC Service Module 5.x
Article Properties
Article Number: 000177295
Article Type: Solution
Last Modified: 11 Sep 2025
Version:  6
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