Excel: Function for nslookup in worksheet

Just a copy of a function I found in a blog post for doing nslookup calls in a worksheet, in case I need it again in the future. I've changed the return value for failing lookups to a blank string, "", rather than "NotFound", but otherwise it's unchanged.

Public Function NSLookup(lookupVal As String, Optional addressOpt As Integer) As String
   Const ADDRESS_LOOKUP = 1
   Const NAME_LOOKUP = 2
   Const AUTO_DETECT = 0

   'Skip everything if the field is blank
   If lookupVal <> "" Then
        Dim oFSO As Object, oShell As Object, oTempFile As Object
        Dim sLine As String, sFilename As String
        Dim intFound As Integer
        Set oFSO = CreateObject("Scripting.FileSystemObject")
        Set oShell = CreateObject("Wscript.Shell")

        'Handle the addresOpt operand
        'Regular Expressions are used to complete a substring match for an IP Address
        'If an IP Address is found, a DNS Name Lookup will be forced
        If addressOpt = AUTO_DETECT Then
            ipLookup = FindIP(lookupVal)
            If ipLookup = "" Then
                addressOpt = ADDRESS_LOOKUP
            Else
                addressOpt = NAME_LOOKUP
                lookupVal = ipLookup
            End If
        'Do a regular expression substring match for an IP Address
        ElseIf addressOpt = NAME_LOOKUP Then
            lookupVal = FindIP(lookupVal)
        End If

        'Run the nslookup command
        sFilename = oFSO.GetTempName
        oShell.Run "cmd /c nslookup " & lookupVal & " > " & sFilename, 0, True
        Set oTempFile = oFSO.OpenTextFile(sFilename, 1)
        Do While oTempFile.AtEndOfStream <> True
            sLine = oTempFile.Readline
            cmdStr = cmdStr & Trim(sLine) & vbCrLf
        Loop
        oTempFile.Close
        oFSO.DeleteFile (sFilename)

        'Process the result
        intFound = InStr(1, cmdStr, "Name:", vbTextCompare)
        If intFound = 0 Then
            NSLookup = ""
            Exit Function
        ElseIf intFound > 0 Then
            'TODO: Cleanup with RegEx
            If addressOpt = ADDRESS_LOOKUP Then
                loc1 = InStr(intFound, cmdStr, "Address:", vbTextCompare) + InStr(intFound, cmdStr, "Addresses:", vbTextCompare)
                loc2 = InStr(loc1, cmdStr, vbCrLf, vbTextCompare)
                nameStr = Trim(Mid(cmdStr, loc1 + 8, loc2 - loc1 - 😎)
            ElseIf addressOpt = NAME_LOOKUP Then
                loc1 = InStr(intFound, cmdStr, "Name:", vbTextCompare)
                loc2 = InStr(loc1, cmdStr, vbCrLf, vbTextCompare)
                nameStr = Trim(Mid(cmdStr, loc1 + 5, loc2 - loc1 - 5))
            End If
        End If
        NSLookup = nameStr
    Else
        NSLookup = "N/A"
    End If
End Function

Function FindIP(strTest As String) As String
    Dim RegEx As Object
    Dim valid As Boolean
    Dim Matches As Object
    Dim i As Integer
    Set RegEx = CreateObject("VBScript.RegExp")

    RegEx.Pattern = "\b(?:\d{1,3}\.){3}\d{1,3}\b"
    valid = RegEx.test(strTest)
    If valid Then
        Set Matches = RegEx.Execute(strTest)
        FindIP = Matches(0)
    Else
        FindIP = ""
    End If
End Function

Usage, given an IP in cell A1, to get the hostname:

=NSLookup(A1; 2)