Solved Reliable way to always return the same code for the MACAddress

Posted on 2014-02-19
Last Modified: 2014-02-27

The following function always returned my machine's MAC addresss but suddenly returns a blank string. Why might the cause be?

    Friend Function GetMACAddress() As String

        Dim mc As ManagementClass = New ManagementClass("Win32_NetworkAdapterConfiguration")
        Dim moc As ManagementObjectCollection = mc.GetInstances()
        Dim MACAddress As String = String.Empty
        For Each mo As ManagementObject In moc

            If (MACAddress.Equals(String.Empty)) Then
                If CBool(mo("IPEnabled")) Then MACAddress = mo("MacAddress").ToString()

            End If
            MACAddress = MACAddress.Replace(":", String.Empty)

        Return MACAddress
    End Function

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The function below seems to work better but it said that that  only refers to the first network adapter
    Function getMacAddress()
        Dim nics() As NetworkInterface = _
        Return nics(0).GetPhysicalAddress.ToString
    End Function

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What is a reliable way to always return the same code for the MACAddress
Question by:murbro
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LVL 83

Expert Comment

ID: 39870171
Problem with your first function is that it loops through the network adaptors and returns you MAC of the last adaptor in the loop. Problem with second function is that it always returns MAC of the first adaptor. What is your requirement? Always return the same MAC? Or always return some MAC?

Author Comment

ID: 39870283
It is to always return the same MAC
LVL 83

Expert Comment

ID: 39870410
I don't know the context of your program but may be you run this function to get a valid MAC once and then store the MAC somewhere instead of calling this function every time.
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Author Comment

ID: 39879048
I am using the MAC address as a way to identify a valid user so it is stored in my cloud SQL
database. Each time the user connects my code validates that the MAC address is the same. So I am just looking for a way to return the same MAC address
LVL 83

Accepted Solution

CodeCruiser earned 500 total points
ID: 39885332
One option then is to get MAC addresses of all the physical NICs in user's computer and then if any of the MACs matches with the one that you have in your database then its a known user.

Author Closing Comment

ID: 39893892
thanks very much

Author Comment

ID: 39893898

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