Is an Internet Connection Available?

Checking whether an Internet connection is available isn’t always as easy as it sounds.
Admittedly, there is a Windows API call that can check whether a connection exists, but it’s extremely fragile and returns incorrect results if the machine has never had Internet Explorer configured correctly. Oops.

The best method is to actually make a Web request and see whether it works. If it does, you’ve got your connection. The following neat code snippet does exactly that. Just call IsConnectionAvailable and check the return value:

Public Function IsConnectionAvailable() As Boolean
    ' Returns True if connection is available
    ' Replace with a site that
    ' is guaranteed to be online - perhaps your
    ' corporate site, or
    Dim objUrl As New System.Uri("")
    ' Setup WebRequest
    Dim objWebReq As System.Net.WebRequest
    objWebReq = System.Net.WebRequest.Create(objUrl)
    Dim objResp As System.Net.WebResponse
        ' Attempt to get response and return True
        objResp = objWebReq.GetResponse
        objWebReq = Nothing
        Return True
    Catch ex As Exception
        ' Error, exit and return False
        objWebReq = Nothing
        Return False
    End Try

Here’s how you might use this function in your application:

If IsConnectionAvailable() = True Then
    MessageBox.Show("You are online!")
End If

You might also like...


Karl Moore


Why not write for us? Or you could submit an event or a user group in your area. Alternatively just tell us what you think!

Our tools

We've got automatic conversion tools to convert C# to VB.NET, VB.NET to C#. Also you can compress javascript and compress css and generate sql connection strings.

“The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'That's funny...'” - Isaac Asimov