B4X

Check Internet Connectivity

See more Socket/SSL/TLS Examples

Demonstrates an efficient way to test for Internet connectivity. B4X

Dim success As Boolean = False

Dim socket As ChilkatSocket
socket.Initialize("socket")
'  1. Use a reliable Anycast IP. 
'     8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) are the industry standards.
Dim targetIp As String = "8.8.8.8"

'  2. Use Port 53 (DNS). 
'     DNS servers typically listen on TCP Port 53 as well as UDP. 
'     (Alternatively, use port 443 if you suspect port 53 is blocked).
Dim port As Int = 53

'  3. Disable SSL (0). 
'     We are not doing a handshake, just a TCP connection.
Dim ssl As Boolean = False

'  4. Short Timeout (1500ms).
'     If you can't reach Google in 1.5 seconds, the connection is 
'     likely too poor for practical use anyway.
Dim timeoutMs As Int = 1500

'  Connect
success = socket.Connect(targetIp, port, ssl, timeoutMs)
If success = False Then
    Log(socket.LastErrorText)
    Return
End If


socket.Close(10)

Log("We have Internet connectivity.")