(PureBasic) Check Internet Connectivity

Demonstrates an efficient way to test for Internet connectivity.

Chilkat PureBasic Module Download Chilkat PureBasic Module

IncludeFile "CkSocket.pb"

Procedure ChilkatExample()

    success.i = 0

    socket.i = CkSocket::ckCreate()
    If socket.i = 0
        Debug "Failed to create object."
        ProcedureReturn
    EndIf

    ; 1. Use a reliable Anycast IP. 
    ;    8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) are the industry standards.
    targetIp.s = "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).
    port.i = 53

    ; 3. Disable SSL (0). 
    ;    We are not doing a handshake, just a TCP connection.
    ssl.i = 0

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

    ; Connect
    success = CkSocket::ckConnect(socket,targetIp,port,ssl,timeoutMs)
    If success = 0
        Debug CkSocket::ckLastErrorText(socket)
        CkSocket::ckDispose(socket)
        ProcedureReturn
    EndIf

    CkSocket::ckClose(socket,10)

    Debug "We have Internet connectivity."


    CkSocket::ckDispose(socket)


    ProcedureReturn
EndProcedure