POP vs. IMAP: Email Protocols and Postfix Mail Server
POP vs. IMAP: Understanding Email Protocols
Let’s delve into the differences between two major email protocols: POP (Post Office Protocol) and IMAP (Internet Message Access Protocol).
POP (Post Office Protocol)
- Designed for accessing emails online, especially for users without a permanent internet connection.
- Can be somewhat heavy for the server.
- Operates on a connect, download, and disconnect scheme.
- Simple protocol with 13 commands that respond with either “+OK” or “-ERR”.
- Default behavior: Downloads
JWT Authentication and RabbitMQ for Microservices
JWT Authentication for a Secure REST API
Server-Side Implementation
import jwt
from flask import Flask, request, jsonify
app = Flask(__name__)
SECRET_KEY = 'coen4246313'
# Secured API route
@app.route('/secure-data', methods=['GET'])
def secure_data():
token = request.headers.get('Authorization')
if not token:
return jsonify({"error": "Missing token"}), 401
try:
# Extract the token from the 'Bearer' scheme
token = token.split(" ")[1]
# Validate the Computer Architecture: From Firmware to Cache Memory
Firmware and Software
Firmware refers to specific instructions recorded in non-volatile memory (ROM, Flash, etc.). It’s the low-level logic that controls a physical device. Assembler, a low-level language, is a more direct representation of machine code. It is used especially when we want to directly manipulate the hardware. The kernel is the fundamental part of the OS. It’s a software program that facilitates secure access to hardware and manages system resources (CPU, memory, etc.). The OS ensures
Read MoreNetwork Security: Attacks and Defense Strategies
UDP Protocol and the Ping-Pong Effect
In the UDP protocol, port 13 is used for the “daytime” service. A time server that receives a packet to its UDP port 13 will always return a packet to the requester’s IP and UDP port, indicating the server’s current time. If the server does not check the requester’s port number, an attacker can send out one packet to a daytime server and cause a ping-pong effect between two daytime servers.
The ping-pong attack in UDP-based services, such as the Daytime
Assembly Language: Stack, Addressing, RISC, and CISC
Stack
- Activation record (aka Stack Frame): Section of stack containing procedure components
- Call stack: Activation records stacked on each other
- STD Call: Method of adding to the stack and using RET n to deconstruct the stack
- Moves toward the heap. Starts at a high address and decrements when values are added
- PUSH OFFSET value – is 32 bit or 4 bytes ex. zBYTE “Why are you looking at this?”, 0
Order of Adding to Stack:
- Passed parameters: By PUSHing before the procedure call
- Return address: By the procedure
Fundamental Programming Concepts and C Language Essentials
Introduction to Programming
Programming is the process of designing and writing instructions for a computer to perform specific tasks. These instructions are written in programming languages, such as Python, Java, C++, or JavaScript. The goal of programming is to solve problems, automate tasks, or create software applications.
What is a Programming Language?
A programming language is a formal set of rules and syntax that allows humans to communicate with computers. Programming languages provide the
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