RFC(request for comments) 9110 and 9112

why http and not tcp? -> tcp guarentee that your data is inorder and complete. it doesnt tell about data format and structure

TCP vs UDP

TCP establishes a connection between sender and receiver with a handshake, and ensures that all the data is sent in order. UDP sends data packets without guarantees about order or delivery.

When data is sent over a network, it is sent in packets. Each message is split into packets, the packets are sent, they arrive (potentially) out of order, and they are reassembled on the other side. And without a protocol like TCP, you can’t guarantee that the order is correct

file vs network streams

When you read from a file, you’re in control of the reading process. You decide:

When to read How much to read When to stop reading. You pull data from the file.

When you read from a network connection, the data is pushed to you by the remote server. You don’t have control over when the data arrives, how much arrives, or when it stops arriving. Your code has to be ready to receive it when it comes.

HTTP Message Structure

Part	Example	Description
start-line CRLF	POST /users/primeagen HTTP/1.1	The request or status line
*( field-line CRLF )	Host: google.com	Zero or more HTTP header lines (key-value pairs)
CRLF		Blank line separating headers from body
[ message-body ]	{"name": "TheHTTPagen"}	Optional message body

cURL is a command line tool for making HTTP requests.

SSH

SSH is a client-server protocol.

The Server: The remote machine (e.g., an AWS EC2 instance or a Raspberry Pi) runs an SSH daemon (sshd) that listens on Port 22.

The Client: Your machine runs an SSH client (like ssh in terminal or PuTTY).

When they connect, they perform a “handshake” to create an encrypted channel. Once established, everything sent over that connection (commands, passwords, files) is scrambled so hackers cannot read it.