Dec 222014

This is an experimental PowerShell script that looks at all the physical network adapters on a machine and verifies that they are at or above an arbitrary link speed set in the script. It works by querying the MSNdis_LinkSpeed class in WMI, filtering out non-physical adapters, and then checking each one to make sure the link speed is above the $MinSpeed value that you set. It then returns TRUE or FALSE.

I believe it is useful to use a greator than or equal to comparison instead of saying that all links must equal the minimum speed, especially in server environments where you may have a mixed environment of some servers with gigabit links for instance, and then another set of servers or virtual machines with 10gig links.

I don’t see this being useful in a PC environment because you have less control over what a desktop is hooked in to at any given point in time. Though it may still be useful if you want to enforce such a policy, like trading floor must be at gigabit or higher, and you want to catch non-compliance.

Obviously I can’t account for every InstanceName that isn’t a physical adapter. If there is a better way, by all means let me know and I’ll modify the script, but here it is!

# Robert's experimental NIC speed compliance script. 
# Emphasis on EXPERIMENTAL. 
# It will not break anything but it may not give back a sane result. 
# Manually check suspect compliance, bad compliance will probably come
# from non-physical nics where I didn't account for the InstanceName
# below when it came from MSNdis_LinkSpeed. 

# Minimum allowed speed in megabits. 
$MinSpeed = '1000' 

# This is used for compliancy.
$NonCompliant = 0

# Get link speed for all physical network adapters. 
$nics = Get-WmiObject -Namespace root\wmi -Class MSNdis_LinkSpeed | where {`
$_.InstanceName -notlike '*miniport*' -and `
$_.InstanceName -notlike '*WAN*' -and `
$_.InstanceName -notlike '*1394*' -and `
$_.InstanceName -notlike '*ISATAP*' -and `
$_.InstanceName -notlike '*Bluetooth*' -and `
$_.InstanceName -notlike '*RAS*' -and `
$_.InstanceName -notlike 'Direct Parallel' -and `
$_.InstanceName -notlike '*tunnel*' -and `
$_.InstanceName -notlike '*6to4*' -and `
$_.InstanceName -notlike '*Deterministic*' -and `
$_.InstanceName -notlike '*miniport*' -and `
$_.InstanceName -notlike '*kernel*'

# Go through list of NICS and make sure speed is above $MinSpeed
foreach ($nic in $nics) {
    #Make the link speed in megabits instead of bits.
    $LinkSpeed = $nic.NdisLinkSpeed/10000

    #See if this NIC is compliant.
    if ($LinkSpeed -lt $MinSpeed) {

# Am I compliant?
if ($NonCompliant -eq 0) {
    write-host TRUE
    } else {
    write-host FALSE
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