public static void main(String[] args) {
        for(int i=0;i<256;i++)
            for(int j=0;j<256;j++)
                for (int port=1025;port<256*256;port++) {
                    boolean ok  = true;
                    try {
                        String address = "192.168."+Integer.toString(i)+"."+Integer.toString(j);
                        Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(address, port));
                        URLConnection conn = new URL("google.ru").openConnection(proxy);
                        //conn.connect(); нужны ли еще действия помимо просто создания соединения
                    } catch (Exception ex) {
                        ok = false;
                        //ex.printStackTrace();
                    } finally {
                        if(ok) System.out.println("192.168."+i+"."+j+":"+port);
                    }
                }
        System.out.println("bruteforce complete");
    }

for(int i=0;i<256;i++)
            for(int j=1;j<256;j++)
                for (int port=1025;port<256*256;port++) { 
                    try {
                        String address = "192.168."+Integer.toString(i)+"."+Integer.toString(j);
                        Proxy proxy = new Proxy(Proxy.Type.HTTP, new InetSocketAddress(address, port));
                        HttpURLConnection  conn = (HttpURLConnection)new URL("http://google.ru").openConnection(proxy);
                        conn.setConnectTimeout(10);
                        conn.connect();
                        System.out.println(conn.getResponseCode());
                        System.out.println("192.168."+i+"."+j+":"+port);
                    } catch (Exception ex) {
                        //ex.printStackTrace();
                    }
                }
        System.out.println("bruteforce complete");