Anonymity – how do LEA and others not track protocol VPN users?

Other questions were asked, but not with the specific details I displayed (no protocol VPN, no leaks, dynamic user agent, and JavaScript disabled).

Hypothetical situation
Someone sends a drone message on Facebook. The criminal installs a new operating system and encrypts his hard drive. They then set up a no-log VPN with a dual VPN function so that even their ISP cannot prove that they are connected to this IP.

When I say a no-log VPN, it means that the VPN provider is running its servers on RAM hard drives.

They ensure that the real IP cannot be lost (DNS leak, etc.) and set up a global kill switch so that no outgoing traffic can be carried out outside the VPN. The Facebook account has a wrong name and is set up via the VPN IP, just like the associated email.

The user goes one step further and starts using a dynamic user agent and deactivates the JavaScript browser far. How does LEA track people who do this and how much effort do they typically invest in such situations?

I understand that the LEA would initiate an investigation by going to the ISP and asking for an IP address and email associated with that account. The IP and email would lead to the IP of the VPN provider.

The LEA would then go to the VPN provider and request all the information associated with that IP (connections, connected IPs, session times, customers connected to this IP).

The VPN provider cannot pass on any information, since all servers are running on RAM disks and nothing is retained. You are in a dead end at the VPN provider.

You are probably trying to do something with the email. The email gives them all the information they have about them and may even force the email provider to track this email, but it doesn't show any information that isn't classified as evidence, not even that most of the time.

To people who say "How logless the VPN really is"

I understand that many providers have been proven to lie about it in legal proceedings. For this post, let's assume that the VPN provider has been checked, its servers have been seized, and it has been proven in court that it does not keep logs. I understand that this can change at any time, but for the sake of this question, let's say they don't keep logs.

Linux – When sending email, check for any live mail protocol errors

I need help with the command to put on my vps. I want to read the email log to check for errors so I can report it to Hotmail. I quickly googled and tried to find the live mail log to look for errors when sending the email.

I use Centos 8 OS and the name of the software I use to send the email is exim.

Do you know what command to use to check for live mail logs to determine if there was an error sending the email or not?

Thanks a lot.

DMA and SRAM USB device or USB protocol

USB devices have SRAM and DMA submodules:

  1. What role does SRAM play in USB devices?
  2. a. How does the DMA controller know that it is initiating a memory request (either read or write)?
    b. How does endpoint get data from buffers and how does endpoint write data to the buffer?
    c. Who is calling the DMA controller to initiate a request to the storage device?

Please clarify the questions listed above.

Algorithms – Why does MergeSort have O (n) space complexity when it divides the array protocol (s) times?

I know that this is a common algorithm with a lot of analysis, but when I was looking for an answer, all I found was "Merge Sorting has O (n) Auxiliary Space because it copies the array into L and R".

I don't understand this because it is called recursively before operations are performed, the entire array is still divided log (n) times. If we follow the binary tree diagram that represents the recursion, we see (if n = 16) that it divides into 2×8, 4×4, 8×2, 16×1.

Since all of these divisions occur before merging, why is the auxiliary space O (n) and not O (nlog (n))?

Is there any good evidence to prove the trustworthiness of a simple blockchain-based protocol?

I want to learn how to check the trustworthiness of a blockchain based protocol, so I'm looking for a simple example. In particular, I want to know which formal system is suitable for the job and how it can be applied to the properties of the blockchain.

Extracted from the Wikipedia article on BAN logic:

In some cases, a protocol was considered safe by the BAN analysis, but was actually unsafe. As a result, the logic of the BAN family has been abandoned in favor of methods of proof based on standard invariance arguments.

Does anyone know what "proof methods based on standard invariance arguments" the author is writing about?

SQL Server 2012 – Index Fragmentation – Protocol Problems

I have a few questions that I want to understand to make an informed decision. I am not a DBA by profession, I have done some administrative work in the past, and I should now have maintenance plans for some of my new servers and understand the problems with my old servers.

1) My database log size is 50 GB (convert MB to GB) and when I use the following query:

SELECT name, size / 128.0 FileSizeInMB,
SIZE / 128.0 – CAST (FILEPROPERTY (Name, & # 39; SpaceUsed & # 39;) AS int) /128.0
AS EmptySpaceInMB
FROM sys.database_files;

It consistently returns 25 GB as empty space. My database is in full recovery mode with hourly log backup. Isn't this log file shortened sometime after the hourly transaction backup and the log file size is reduced?

2) We created a defragmentation plan at night. This plan runs for 15 minutes and rebuilds all indexes above 40% level of fragmentation. The DBA of one of our providers explains that the tables are locked during the new creation and the log file therefore grows. I don't understand it clearly.
Aren't the log files growing both during recovery and reorganization? Can't a long runtime quickly reorganize log populations?

3) How often should we update statistics after a daily index is reorganized – immediately or weekly / monthly?

Many thanks.

Javascript – How to fix the error: The client does not support the authentication protocol requested by the server. Consider upgrading the MySQL client

I am starting an application and want to retrieve the data from an existing database in phpMyAdmin. When I try to do this in the node, the following error message is displayed: The client does not support the authentication protocol requested by the server. Consider upgrading the MySQL client. Follow the code below:

const express = require('express');
const mysql = require('mysql');

const db = mysql.createConnection({
    host: 'localhost',
    user: 'root',
    password: '123456',
    database: 'monitor'

db.connect((err) => {
    if (err) {
        throw err;
    console.log('MySQL Connected');

const app = express();

app.listen('3000', () => {
    console.log('Server Started on port 3000');

Computer networks – sending infinite frames in the one-bit sliding Windows protocol?

I read Computer networks by Andrew S. Tanenbaum and I wonder if the log contains an error because I can't find a solution for the following scenario.

Assume that the transmitter (A) has only one frame (X) to send and the receiver (B) has nothing to send. B receives X and sends a frame with an empty information field and an acknowledgment from X to A. However, for A this triggers the frame_arrival event, which in turn causes A to send an "acknowledgment" to B again without a packet (because it is only gave one). And so the ping-pong of completely useless frames goes on and on. Is this an error in the protocol, in the pseudocode of the protocol or am I wrong?

I take this sequence number frame_expected A will disagree with B's second confirmation.

One-bit sliding protocol