Java

Check Internet Connectivity

See more Socket/SSL/TLS Examples

Demonstrates an efficient way to test for Internet connectivity. Chilkat2 Java

import com.chilkatsoft.chilkat2.ChilkatException;
import com.chilkatsoft.chilkat2.Socket;

public class ChilkatExample {

    public static void main(String[] args) {
        Socket socket = new Socket();
        // 1. Use a reliable Anycast IP.
        //    8.8.8.8 (Google) or 1.1.1.1 (Cloudflare) are the industry standards.
        String 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).
        int port = 53;

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

        // Connect
        try {
            socket.connect(targetIp, port, ssl, timeoutMs);
        } catch (ChilkatException e) {
            System.out.println(e.getLastErrorText());
            return;
        }

        socket.closeConnection(10);

        System.out.println("We have Internet connectivity.");
    }
}