Check internet connection state

There is plenty of code around to show you how to detect connections to the internet when using Dial Up Networking. But how about internet connections over a LAN? This code solves your problems.

Add this code to a module :

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

Public Const INTERNET_CONNECTION_LAN As Long = &H2
Public Const INTERNET_CONNECTION_MODEM As Long = &H1

Public Function Online() As Boolean
    'If you are online it will return True, otherwise False
    Online = InternetGetConnectedState(0& ,0&)
End Function

Public Function ViaLAN() As Boolean

Dim SFlags As Long
'return the flags associated with the connection
Call InternetGetConnectedState(SFlags, 0&)

'True if the Sflags has a LAN connection
ViaLAN = SFlags And INTERNET_CONNECTION_LAN

End Function
Public Function ViaModem() As Boolean

Dim SFlags As Long
'return the flags associated with the connection
Call InternetGetConnectedState(SFlags, 0&)

'True if the Sflags has a modem connection
ViaModem = SFlags And INTERNET_CONNECTION_MODEM

End Function

Add this code to a form with one command button and three text boxes. It will return "True" for which ever one you are connected to.

Option Explicit 

Private Sub Command1_Click() 
Text1 = ViaLAN() 
Text2 = ViaModem() 
Text3 = Online()
End Sub 

Thanks to Hutchie and various others on the Q and A forums for this tip.