Single Proxy

You need to go to "Settings", under "Sharing" select "VPN". And there you can either enter the connection parameters manually (address, port number, username and password), or choose a program that automatically connects the user to the proxy (free applications of this type can be found in Google Play).

To scrape JSON data using RxJava in a Java application, you can use the RxJava library along with an HTTP client library to make requests. Below is an example using RxJava2 and OkHttp to scrape JSON data from a URL asynchronously.

Add Dependencies

Add the following dependencies to your project:

    io.reactivex.rxjava2
    rxjava
    2.x.y 




    com.squareup.okhttp3
    okhttp
    4.x.y 

Write the Code:

import io.reactivex.Observable;
import io.reactivex.schedulers.Schedulers;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public class JsonScrapingExample {

    public static void main(String[] args) {
        String url = "https://api.example.com/data"; // Replace with your JSON API URL

        // Create an Observable that emits a single item (the URL)
        Observable.just(url)
                .observeOn(Schedulers.io()) // Specify the IO thread for network operations
                .map(JsonScrapingExample::fetchJson)
                .subscribe(
                        jsonData -> {
                            // Process the JSON data (replace this with your scraping logic)
                            System.out.println("Scraped JSON data: " + jsonData);
                        },
                        Throwable::printStackTrace
                );
    }

    // Function to fetch JSON data using OkHttp
    private static String fetchJson(String url) throws Exception {
        OkHttpClient client = new OkHttpClient();
        Request request = new Request.Builder()
                .url(url)
                .build();

        try (Response response = client.newCall(request).execute()) {
            if (!response.isSuccessful()) {
                throw new Exception("Failed to fetch JSON. HTTP Code: " + response.code());
            }

            // Return the JSON data as a string
            return response.body().string();
        }
    }
}

2. • Replace the url variable with the actual URL of the JSON API you want to scrape.
   • The fetchJson function uses OkHttp to make an HTTP request and fetch the JSON data.

3. Run the Code:

   • Execute the Java code to fetch and process the JSON data asynchronously using RxJava.

This example uses RxJava's Observable to create an asynchronous stream of events. The observeOn(Schedulers.io()) part specifies that the network operation (fetchJson) should run on the IO thread to avoid blocking the main thread.

Make sure to handle exceptions appropriately and adjust the code based on the structure of the JSON API you are working with.

Fail2Ban is a security tool that analyzes log files for malicious patterns and bans IP addresses that show suspicious activity. Although Fail2Ban is primarily designed to work with TCP-based protocols like SSH, HTTP, and MySQL, it can be configured to work with UDP-based protocols, including UDP flood attacks.

To use Fail2Ban to protect your server from UDP flood attacks, follow these steps:

1. Install Fail2Ban:

sudo apt-get update
sudo apt-get install fail2ban

2. Create a custom UDP log file:

Create a log file to store the UDP flood attack data. This log file should be located in the /var/log/ directory, and it should have the appropriate permissions. For example, you can create a log file named udp-flood.log:

sudo touch /var/log/udp-flood.log
sudo chown syslog:adm /var/log/udp-flood.log
sudo chmod 640 /var/log/udp-flood.log

3. Configure Fail2Ban to monitor the UDP log file:

Create a new filter file for UDP flood attacks, for example, /etc/fail2ban/filter.d/udp-flood.conf:

[Definition]
failregex = ^.*UDP.*Flood.*
ignoreregex =

Replace HOST with the actual hostname or IP address of your server, and with the IP address of the attacking host.

Next, create a new action file for UDP flood attacks, for example, /etc/fail2ban/action.d/udp-flood.conf:

[Definition]
actionstart =
actionstop =
actioncheck =
actionban = iptables -I INPUT -s  -j DROP; iptables-save
actionunban = iptables -D INPUT -s  -j DROP; iptables-save

Replace IP with the IP address of the banned host.

Finally, create a new jail configuration file for UDP flood attacks, for example, /etc/fail2ban/jail.d/udp-flood.local.conf:

[udp-flood]
enabled = true
port = 
logpath = /var/log/udp-flood.log
maxretry = 3
findtime = 300
bantime = 1800
action = udp-flood

Replace UDP_PORT with the UDP port you want to monitor.

Reload Fail2Ban configuration:

sudo systemctl reload fail2ban

Transferring a large byte array using UDP involves breaking the data into smaller chunks and sending each chunk as a separate UDP datagram. Since UDP is a connectionless protocol, there's no guarantee that the chunks will arrive in the same order they were sent. Therefore, you'll also need to send additional information to reassemble the data correctly at the receiver side.

Here's a simple example using Python to send and receive large byte arrays using UDP:

1. Sender (Python script send_large_data.py):

import socket

def send_large_data(data, host, port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    chunk_size = 1024

    total_chunks = len(data) // chunk_size + 1
    sequence_number = 0

    for i in range(total_chunks):
        start = sequence_number * chunk_size
        end = start + chunk_size
        chunk = data[start:end]

        sock.sendto(chunk, (host, port))
        sequence_number += 1

    sock.close()

if __name__ == "__main__":
    large_data = b"This is a large byte array sent using UDP." * 100
    host = "127.0.0.1"
    port = 12345
    send_large_data(large_data, host, port)

2. Receiver (Python script receive_large_data.py):

import socket

def receive_large_data(host, port):
    sock = socket.socket(socket.AF_INET, socket.SOCK_DGRAM)
    chunk_size = 1024
    total_chunks = 0
    received_data = b""

    while True:
        data, address = sock.recvfrom(chunk_size)
        total_chunks += 1
        received_data += data

        if len(received_data) >= (total_chunks - 1) * chunk_size:
            break

    sock.close()
    return received_data

if __name__ == "__main__":
    host = "127.0.0.1"
    port = 12345
    large_data = receive_large_data(host, port)
    print("Received data:", large_data)

In this example, the sender script send_large_data.py breaks the large byte array into chunks of 1024 bytes and sends each chunk as a separate UDP datagram. The receiver script receive_large_data.py receives the chunks and reassembles them into the original byte array.

It means organizing a connection through several VPN-servers at once. It is used to protect confidential data as much as possible or to hide one's real IP address. This principle of connection is used, for example, in the TOR-browser. That is, when all traffic is sent immediately through a chain of proxy servers.