1. HTTP - hyper text transfer protocol
HTTP is a protocol that helps fetch resources like HTML documents, forming the backbone of all data exchanges on the web. It works on a client-server model, meaning the client (usually your web browser) starts the conversation by making a request, and the server responds with the requested data.
When you load a webpage, it's actually built from many pieces—text, images, videos, scripts, and more—coming together like a puzzle.
Here’s how it works:
Clients and Servers talk by sending messages.
A client sends a request.
The server replies with a response.
Now, let’s break it down further:
Protocol: Think of it as a set of rules or guidelines for exchanging data. Just like everyone needs to follow road rules for smooth traffic, computers need protocols to ensure clear communication.
Hypertext: This is what makes the web so cool! Hypertext is the magic behind linking different pages or resources together with hyperlinks, so you can easily jump from one place to another online.
2. Session and cookies
Cookies:
Definition: Small pieces of data stored on the user's browser.
Storage: Stored on the client-side (browser).
Purpose: Used for remembering user preferences, tracking, and maintaining information across sessions (e.g., login credentials, shopping carts).
Scope: Sent with every HTTP request to the server.
Lifespan: Can persist until a specified expiration date or until the user clears them.
Security: Vulnerable to client-side attacks like Cross-Site Scripting (XSS).
Sessions:
Definition: Temporary data stored on the server for a specific user.
Storage: Stored server-side, with a unique session ID shared with the client via cookies or URLs.
Purpose: Used for secure, temporary data storage during user interaction (e.g., authentication tokens, user preferences).
Scope: Exists only while the user is actively interacting or until the session times out.
Lifespan: Ends when the user logs out, or the session expires.
Security: More secure as sensitive data is not stored on the client-side.
Key Difference:
Cookies are client-side and persistent.
Sessions are server-side and temporary.
They often work together, where cookies store session IDs to identify users on the server. sessions are maintained by cookies
3. HTTP Headers
Client.
Browser Info.
Date Time.
Cookie to store.
4. Request - Response Model
The Request-Response Model is a communication pattern where a client (e.g., a browser) sends a request to a server, and the server processes the request and sends back a response. It forms the basis of protocols like HTTP, where clients request resources (like web pages) and servers deliver them.
5. HTTP 2
HTTP/2 is an advanced version of HTTP that improves performance and efficiency. Key features include multiplexing (multiple requests in one connection), header compression, and server push, which speeds up web page loading and reduces latency.
6. TLS- Transport Layer Security
TLS is a cryptographic protocol that provides secure communication over the internet. It encrypts data to ensure privacy and data integrity between clients and servers, making it essential for secure protocols like HTTPS. It replaced the older SSL protocol.
8. TCP (Transmission Control Protocol).
TCP (Transmission Control Protocol) is an important network protocol that lets two hosts connect and exchange data streams. TCP guarantees the delivery of data and packets in the same order as they were sent. TCP's role is to ensure the packets are reliably delivered, and error-free.
9. FTP (File Transfer Protocol).
FTP or File Transfer Protocol is said to be one of the earliest and also the most common forms of transferring files on the internet. Located in the application layer of the OSI model, FTP is a basic system that helps in transferring files between a client and a server.
10. IP (Internet Protocol).
A network-layer protocol responsible for addressing and routing data packets between devices across networks.
11. URL (Uniform Resource Locator).
A URL (Uniform Resource Locator) is the address of a unique resource on the internet. It is one of the key mechanisms used by browsers to retrieve published resources, such as HTML pages, CSS documents, images, and so on.
12. DNS (Domain Name System/Server).
DNS translates domain names (e.g., example.com) into IP addresses (e.g., 192.168.1.1) that computers use to communicate. It's like the internet's phonebook, enabling user-friendly web browsing.
13. Header (Pass aditional information).
In networking or data transfer, a header contains metadata about the message, such as sender/receiver info, protocol type, and data length. It's essential for ensuring correct delivery and processing of the data.
14. Payload.
The payload is the actual data being transmitted in a network packet or message, excluding headers or metadata. For example, the content of an email or file in a data packet is the payload.
15. Cache (Store the data).
A cache is a temporary storage mechanism that saves frequently accessed data (e.g., web pages, images) to improve performance and reduce loading times. It minimizes the need to fetch the same data repeatedly from the source.