Various Methods to Detect / Test Internet Connection

' ---------------
' Put in Module
' ---------------

Option Explicit

Public Declare Function InternetGetConnectedState _
    Lib "wininet.dll" (ByRef lpdwFlags As Long, _
    ByVal dwReserved As Long) As Long

    ' Local system uses a modem to connect to the Internet
    Public Const INTERNET_CONNECTION_MODEM As Long = &H1

    ' Local system uses a LAN to connect to the Internet.
    Public Const INTERNET_CONNECTION_LAN As Long = &H2

    ' Local system uses a proxy server to connect to the Internet.
    Public Const INTERNET_CONNECTION_PROXY As Long = &H4

    ' No longer used
    Public Const INTERNET_CONNECTION_MODEM_BUSY As Long = &H8
    Public Const INTERNET_RAS_INSTALLED As Long = &H10
    Public Const INTERNET_CONNECTION_OFFLINE As Long = &H20
    Public Const INTERNET_CONNECTION_CONFIGURED As Long = &H40

' -------------------------------------------
' InternetGetConnectedState wrapper functions
' -------------------------------------------

Public Function IsNetConnectViaLAN() As Boolean
    Dim dwflags As Long
    'pass an empty varialbe into which the API will
    'return the flags associated with the connection
    Call InternetGetConnectedState(dwflags, 0&)

    'return True if the flags indicate a LAN connection
    IsNetConnectViaLAN = dwflags And INTERNET_CONNECTION_LAN
End Function

Public Function IsNetConnectViaModem() As Boolean
    Dim dwflags As Long
    'pass an empty varialbe into which the API will
    'return the flags associated with the connection
    Call InternetGetConnectedState(dwflags, 0&)

    'return True if the flags indicate a modem connection
    IsNetConnectViaModem = dwflags And INTERNET_CONNECTION_MODEM
End Function

Public Function IsNetConnectViaProxy() As Boolean
    Dim dwflags As Long
    'pass an empty varialbe into which the API will
    'return the flags associated with the connection
    Call InternetGetConnectedState(dwflags, 0&)

    'return True if the flags indicate a proxy connection
    IsNetConnectViaProxy = dwflags And INTERNET_CONNECTION_PROXY
End Function

Public Function IsNetConnectOnline() As Boolean
    'no flags needed here - the API returns True
    'if there is a connection of any type
    IsNetConnectOnline = InternetGetConnectedState(0&, 0&)
End Function

Public Function IsNetRASInstalled() As Boolean
    Dim dwflags As Long
    'pass an empty varialbe into which the API will
    'return the flags associated with the connection
    Call InternetGetConnectedState(dwflags, 0&)

    'return True if the falgs include RAS installed
    IsNetRASInstalled = dwflags And INTERNET_RAS_INSTALLED
End Function

Public Function GetNetConnectString() As String
    Dim dwflags As Long
    Dim msg As String

    'build a string for display
    If InternetGetConnectedState(dwflags, 0&) Then
        If dwflags And INTERNET_CONNECTION_CONFIGURED Then
            msg = msg & "You have a network connection configured." & vbCrLf
        End If

        If dwflags And INTERNET_CONNECTION_LAN Then
            msg = msg & "The local system connects to the Internet via a LAN"
        End If

        If dwflags And INTERNET_CONNECTION_PROXY Then
            msg = msg & ", and uses a proxy server. "
        Else: msg = msg & "."
        End If

        If dwflags And INTERNET_CONNECTION_MODEM Then
            msg = msg & "The local system uses a modem to connect to the Internet. "
        End If

        If dwflags And INTERNET_CONNECTION_OFFLINE Then
            msg = msg & "The connection is currently offline. "
        End If

        If dwflags And INTERNET_CONNECTION_MODEM_BUSY Then
            msg = msg & "The local system's modem is busy With a non-Internet connection. "
        End If

        If dwflags And INTERNET_RAS_INSTALLED Then
            msg = msg & "Remote Access Services are installed On this system."
        End If
    Else
        msg = "Not connected to the internet now."
    End If

    GetNetConnectString = msg
End Function