Module5-NSLookup_NS

'2019-04-22 RookieITSec note - This script was created by somoene else and modified by me.  Found here - https://www.geekality.net/2016/03/07/excel-function-for-nslookup-in-worksheet/ and here https://github.com/cscholz/scripts/blob/master/Windows/VBA/Excel/nslookup.txt
'2019-04-22 RookieITSec note -This pulls the first nameserver for a domain.  Most domains have multiple nameservers, but I only needed the first for validation generally.  

Public Function NSLookup_NS(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 -q=ns " & lookupVal & " 8.8.8.8 " & " > " & 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, "nameserver = ", vbTextCompare)
        If intFound = 0 Then
            NSLookup_NS = "            Exit Function"
        ElseIf intFound > 0 Then
            'TODO: Cleanup with RegEx
                loc1 = intFound
                loc2 = InStr(loc1, cmdStr, vbNewLine, vbTextCompare)
                nameStr = Trim(Mid(cmdStr, loc1 + 13, loc2 - loc1 - 13))
                
        End If
        NSLookup_NS = nameStr
    Else
         



    End If
End Function