VB Function to Find the IP Addresses of the Local Computer

The function below uses the GetIpAddrTable Win32 API call to retrieve all IP addresses of the local machine.

Private Declare Function GetIpAddrTable_API Lib "IpHlpApi" Alias "GetIpAddrTable" (pIPAddrTable As Any, pdwSize As Long, ByVal bOrder As Long) As Long

' Returns an array with the local IP addresses (as strings).
' Author: Christian d'Heureuse, www.source-code.biz
Public Function GetIpAddrTable()
   Dim Buf(0 To 511) As Byte
   Dim BufSize As Long: BufSize = UBound(Buf) + 1
   Dim rc As Long
   rc = GetIpAddrTable_API(Buf(0), BufSize, 1)
   If rc <> 0 Then Err.Raise vbObjectError, , "GetIpAddrTable failed with return value " & rc
   Dim NrOfEntries As Integer: NrOfEntries = Buf(1) * 256 + Buf(0)
   If NrOfEntries = 0 Then GetIpAddrTable = Array(): Exit Function
   ReDim IpAddrs(0 To NrOfEntries - 1) As String
   Dim i As Integer
   For i = 0 To NrOfEntries - 1
      Dim j As Integer, s As String: s = ""
      For j = 0 To 3: s = s & IIf(j > 0, ".", "") & Buf(4 + i * 24 + j): Next
      IpAddrs(i) = s
      Next
   GetIpAddrTable = IpAddrs
   End Function

' Test program for GetIpAddrTable.
Public Sub Test()
   Dim IpAddrs
   IpAddrs = GetIpAddrTable
   Debug.Print "Nr of IP addresses: " & UBound(IpAddrs) - LBound(IpAddrs) + 1
   Dim i As Integer
   For i = LBound(IpAddrs) To UBound(IpAddrs)
      Debug.Print IpAddrs(i)
      Next
   End Sub

Author: Christian d'Heureuse (www.source-code.biz, www.inventec.ch/chdh)
License: Free / LGPL
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