我使用这部分代码来ping通Java中的ip地址，但只有ping通本地主机才能成功，而对于其他主机，程序会说该主机不可访问。我禁用了防火墙，但是仍然有此问题

public static void main(String[] args) throws UnknownHostException, IOException {
    String ipAddress = "127.0.0.1";
    InetAddress inet = InetAddress.getByName(ipAddress);

    System.out.println("Sending Ping Request to " + ipAddress);
    System.out.println(inet.isReachable(5000) ? "Host is reachable" : "Host is NOT reachable");

    ipAddress = "173.194.32.38";
    inet = InetAddress.getByName(ipAddress);

    System.out.println("Sending Ping Request to " + ipAddress);
    System.out.println(inet.isReachable(5000) ? "Host is reachable" : "Host is NOT reachable");
}

输出为：

Sending Ping Request to 127.0.0.1
Host is reachable
Sending Ping Request to 173.194.32.38
Host is NOT reachable