(PHP Extension) Check Internet Connectivity

Demonstrates an efficient way to test for Internet connectivity.

Chilkat PHP Downloads PHP Extension for Windows, Linux, MacOS, Alpine Linux

<?php

include("chilkat.php");

$success = false;

$socket = new CkSocket();
// 1. Use a reliable Anycast IP. 
//    8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) are the industry standards.
$targetIp = '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 = 53;

// 3. Disable SSL (0). 
//    We are not doing a handshake, just a TCP connection.
$ssl = 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.
$timeoutMs = 1500;

// Connect
$success = $socket->Connect($targetIp,$port,$ssl,$timeoutMs);
if ($success == false) {
    print $socket->lastErrorText() . "\n";
    exit;
}

$socket->Close(10);

print 'We have Internet connectivity.' . "\n";

?>