Sometimes you would like to know whether a port is open on a remote machine. Now while this is no nmap, the following code should give you an idea on how to check whether a port is open.
Private Function isRemotePortOpen(ByVal hostName As String, ByVal port As Integer) As Boolean Dim client As TcpClient = Nothing Dim rtn as Boolean Try client = New TcpClient(Host, PortNumber) rtn = True Catch ex As SocketException rtn = False Finally If Not client Is Nothing Then client.Close() End If End Try Return rtn End Function
Check whether a port is open on a remote machine