How to Find the WWN Number in Windows Using PowerShell

To find the WWN number in Windows with PowerShell, run Get-InitiatorPort and filter for Fibre Channel ports. NodeAddress is the WWNN and PortAddress is the WWPN:

Get-InitiatorPort -ConnectionType FibreChannel | Select-Object -Property InstanceName, NodeAddress, PortAddress

Storage admins ask for the WWPN when they zone a switch or map LUNs to a server. Below I format the numbers the way SAN tools expect them, query remote servers, and explain what you see on a PC without a Fibre Channel card.

Run it as administrator

Get-InitiatorPort reads storage information that needs admin rights. From a normal window it fails, as it did on my test laptop:

try { Get-InitiatorPort -ErrorAction Stop }
catch { "Failed. $($_.Exception.Message)" }

Output:

Failed. Access to a CIM resource was not available to the client.

Windows PowerShell 5.1 shows the same error, so open PowerShell with Run as administrator. Get-InitiatorPort also lists iSCSI and SAS ports when they exist. iSCSI uses an IQN name instead of a WWN. If you need another account, see running PowerShell as a different user.

WWNs belong to host bus adapters (HBAs), which servers have and laptops usually don’t. The low-level WMI class for Fibre Channel adapters shows that on my laptop:

try {
    Get-CimInstance -Namespace root\WMI -ClassName MSFC_FCAdapterHBAAttributes -ErrorAction Stop
}
catch { "Failed. $($_.Exception.Message)" }

Output:

Failed. The requested operation is not supported.

PowerShell 7 words it as The requested operation is not supported. On a server with an HBA driver, this class returns the adapter details instead.

Format the WWN with colons

Get-InitiatorPort returns WWNs as 16 hex digits with no separators. Switches and SAN arrays usually show them in pairs separated by colons. This small function converts either style:

function Format-Wwn ([string]$Raw) {
    $hex = $Raw -replace '[^0-9A-Fa-f]', ''
    (($hex.ToLower() -split '(..)') | Where-Object { $_ }) -join ':'
}

Format-Wwn '20000025B500A01F'
Format-Wwn '21-00-00-24-FF-4C-8A-12'

$bytes = [byte[]](0x50, 0x01, 0x43, 0x80, 0x12, 0x34, 0x56, 0x78)
($bytes | ForEach-Object { '{0:x2}' -f $_ }) -join ':'

Output:

20:00:00:25:b5:00:a0:1f
21:00:00:24:ff:4c:8a:12
50:01:43:80:12:34:56:78

The last line converts a byte array, which is how some WMI classes return the WWN. For text stored as bytes, see converting a byte array to a string.

Get the WWNN and WWPN for each port

On a server with a dual-port card, filter for Fibre Channel and format both addresses. I used sample objects with the real property names, since my laptop has no HBA:

function Format-Wwn ([string]$Raw) {
    $hex = $Raw -replace '[^0-9A-Fa-f]', ''
    (($hex.ToLower() -split '(..)') | Where-Object { $_ }) -join ':'
}

$ports = @(
    [pscustomobject]@{ InstanceName = 'PCI\VEN_1077&DEV_2031\0'; NodeAddress = '20000024FF4C8A12'; PortAddress = '21000024FF4C8A12'; ConnectionType = 'FibreChannel' }
    [pscustomobject]@{ InstanceName = 'PCI\VEN_1077&DEV_2031\1'; NodeAddress = '20000024FF4C8A13'; PortAddress = '21000024FF4C8A13'; ConnectionType = 'FibreChannel' }
    [pscustomobject]@{ InstanceName = 'ROOT\ISCSIPRT\0000_0';    NodeAddress = 'iqn.1991-05.com.microsoft:nyc-sql-01'; PortAddress = 'ISCSI ANY PORT'; ConnectionType = 'iSCSI' }
)
$ports | Where-Object ConnectionType -EQ 'FibreChannel' |
    Select-Object -Property @{ Name = 'WWNN'; Expression = { Format-Wwn $_.NodeAddress } },
                            @{ Name = 'WWPN'; Expression = { Format-Wwn $_.PortAddress } }

Output:

WWNN                    WWPN
----                    ----
20:00:00:24:ff:4c:8a:12 21:00:00:24:ff:4c:8a:12
20:00:00:24:ff:4c:8a:13 21:00:00:24:ff:4c:8a:13

The iSCSI port is filtered out. On a real server, replace $ports with Get-InitiatorPort. The filter is a standard Where-Object call.

Get WWNs from remote servers

Get-InitiatorPort accepts -CimSession, so you can collect WWPNs from many servers at once:

$session = New-CimSession -ComputerName 'NYC-SQL-01', 'NYC-SQL-02'
Get-InitiatorPort -CimSession $session -ConnectionType FibreChannel |
    Select-Object -Property PSComputerName, InstanceName, PortAddress
Remove-CimSession -CimSession $session

Export the result to CSV and you have the zoning list for a new SAN in one go. See PowerShell Export-Csv.

Virtual Fibre Channel in Hyper-V

Virtual machines with virtual Fibre Channel adapters have their own WWPNs, two sets per adapter for live migration. Read them on the Hyper-V host:

Get-VMFibreChannelHba -VMName 'SQL-VM01' |
    Select-Object -Property SanName, WorldWidePortNameSetA, WorldWidePortNameSetB

Give the storage team both sets, or live migration fails on the destination host.

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