Option Explicit
 
Type RASCONN
  dwSize As Long
  hRasConn As Long
  szEntryName(256) As Byte
  szDeviceType(16) As Byte
  szDeviceName(128) As Byte
End Type
 
Declare Function RasEnumConnectionsA Lib "RasApi32.DLL" _
  (lpRasConn As Any, lbcp As Long, lbcConnections As Long) _
  As Long

Public Function IsConnected() As Boolean
  Dim lpRasConn(255) As RASCONN
  Dim lpcConnections As Long
  Dim lpcb As Long
  Dim hRasConn As Long
  Dim NameRasConn As String
  Dim x As Integer
 
  lpRasConn(0).dwSize = 412
  lpcb = 256 * lpRasConn(0).dwSize
 
  RasEnumConnectionsA lpRasConn(0), lpcb, lpcConnections
  If lpcConnections < 1 Then
    <font color=green>' es besteht keine DFÜ-Verbindung</font>
    IsConnected = False
  Else
    <font color=green>' es besteht mind. 1 DFÜ-Verbindung</font>
    IsConnected = True
  End If
End Function

If IsConnected() Then
  MsgBox "Jepp - DFÜ-Verbindung aktiv!"
Else
  MsgBox "Keine DFÜ-Verbindung aktiv!"
End If