How can I disconnect from the internet using VB?

If you want to terminate all connections to the internet using Visual Basic, you can use the Remote Access Services Hangup function. You first need to declare the following code in the declaration section of a form or module.

Declarations

Public Const RAS_MAXENTRYNAME As Integer = 256
Public Const RAS_MAXDEVICETYPE As Integer = 16
Public Const RAS_MAXDEVICENAME As Integer = 128
Public Const RAS_RASCONNSIZE As Integer = 412
Public Const ERROR_SUCCESS = 0&

Public Type RasEntryName
    dwSize As Long
    szEntryName(RAS_MAXENTRYNAME) As Byte
End Type

Public Type RasConn
    dwSize As Long
    hRasConn As Long
    szEntryName(RAS_MAXENTRYNAME) As Byte
    szDeviceType(RAS_MAXDEVICETYPE) As Byte
    szDeviceName(RAS_MAXDEVICENAME) As Byte
End Type

Public Declare Function RasEnumConnections Lib _
"rasapi32.dll" Alias "RasEnumConnectionsA" (lpRasConn As _
Any, lpcb As Long, lpcConnections As Long) As Long

Public Declare Function RasHangUp Lib "rasapi32.dll" Alias _
"RasHangUpA" (ByVal hRasConn As Long) As LongPublic gstrISPName As String
Public ReturnCode As Long

Procedure

Public Sub HangUp()
Dim i As Long
Dim lpRasConn(255) As RasConn
Dim lpcb As Long
Dim lpcConnections As Long
Dim hRasConn As Long
lpRasConn(0).dwSize = RAS_RASCONNSIZE
lpcb = RAS_MAXENTRYNAME * lpRasConn(0).dwSize
lpcConnections = 0
ReturnCode = RasEnumConnections(lpRasConn(0), lpcb, _
lpcConnections)

If ReturnCode = ERROR_SUCCESS Then
    For i = 0 To lpcConnections - 1
        If Trim(ByteToString(lpRasConn(i).szEntryName)) _
            = Trim(gstrISPName) Then
            hRasConn = lpRasConn(i).hRasConn
            ReturnCode = RasHangUp(ByVal hRasConn)
        End If
    Next i
End If

End Sub

Public Function ByteToString(bytString() As Byte) As String
Dim i As Integer
ByteToString = ""
i = 0
While bytString(i) = 0&
ByteToString = ByteToString & Chr(bytString(i))
i = i + 1
Wend
End Function

Using the HangUp Procedure

Once you have copied all required code into your project, you can hang up all connections to the telephone network by calling the procudure HangUp:

Call HangUp