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Editorial Team
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Asked: 2026-05-12T15:45:01+00:00

I am using WMI to detect a number of items about a network adapter’s

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I am using WMI to detect a number of items about a network adapter’s state. Among the things I need to find out are (a) speed and (b) duplex.

I have been able to detect the speed of a network adapter by using WMI and the following Python code:

from pycom.client import wmi

dev_name = r"\\DEVICE\\{287EB4BB-5C2A-4108-B377-15E1D0B0E760}"
query1 = """
SELECT * 
FROM  MSNdis_EnumerateAdapter
WHERE DeviceName = '%s'""" % dev_name


wmi_ndis = wmi.WMI("root\\WMI")
results = wmi_ndis.ExecQuery(query1)
instance_name = results[0].InstanceName

del results

query2="""
SELECT * 
FROM MSNdis_LinkSpeed
WHERE InstanceName='%s'""" % instance_name
results = wmi_ndis.ExecQuery(query2)
linkspeed = results[0].NdisLinkSpeed

del results

print instance_name, linkspeed

del instance_name
del linkspeed
del wmi_ndis

There appears to be a perfect class for the data I want: MSNDis_LinkParameters. However, this table does not appear to be populated. There are values in Win32_NetworkAdapter as well, but they are also not populated.

I would be happy to use a native C API or WMI, but I can’t do screen scraping because the application needs to work with arbitrary languages. Thanks!

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1 Answer

  1. Editorial Team

    Apparently the underlying issue here is that WMI provider implementation is handled by the NIC vendor, not the OS– so some NICs may support some settings while (as you’ve discovered) others don’t.

    For link speed, check out this for some WMI scripts which may work on most NICs.

    For duplex, I think you’re out of luck, at least according to topic. Look at the last post in that thread– it seems pretty specific about how to work around the limit in some cases, but won’t work for all NICs.

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