Unit 7.5

Key Internet Protocols: HTTP, Email, and FTP

IT 231: IT and Application

Learning Objectives 🎯

By the end of this chapter, you will be able to:

✅ Define HTTP and its role in the World Wide Web.
✅ Identify the key protocols used for sending and receiving email.
✅ Define FTP and its purpose for file transfers.

Beyond TCP/IP: Application Protocols

While TCP/IP provides the internet's foundation, specialized Application Layer protocols handle the services we use daily.

Think of TCP/IP as the postal service, and these protocols as the different types of mail you can send:

💌 Letters (Email)
📦 Packages (FTP)
📰 Magazines (HTTP)

1. HTTP: The Language of the Web 🌐

HTTP (Hypertext Transfer Protocol) is the protocol that powers the World Wide Web. It defines how browsers and servers communicate.

The process is a simple request-response cycle:

You type a URL in your browser.
Your browser sends an HTTP Request to the web server.
The server sends back an HTTP Response containing the webpage content.

Security Matters: HTTP vs. HTTPS 🔒

HTTP

Standard HTTP
Unencrypted
Data sent in plain text
Vulnerable to interception

HTTPS

HTTP Secure
Encrypted communication
Protects data with SSL/TLS
Essential for sensitive info

Key Point: Always look for the lock icon! HTTPS protects your passwords, credit card numbers, and personal data.

Practical Application in Nepal 🇳🇵

Using Online Services Securely

When you log into a Nepali service like eSewa, Khalti, or your bank's online portal, your browser uses HTTPS.

This encryption is crucial for protecting your financial details and login credentials from being stolen over public Wi-Fi or other insecure networks.

2. How Email Travels: A Team of Protocols 📧

Sending and receiving email isn't handled by a single protocol. It requires a coordinated effort between multiple protocols.

We'll look at the three main players:

SMTP: For sending mail.
POP3: For receiving mail (the old way).
IMAP: For receiving mail (the modern way).

The Email Protocols 📊

SMTP

Simple Mail Transfer Protocol

The standard for SENDING email from a client to a server.

POP3

Post Office Protocol 3

Used for RECEIVING. Downloads email to a single device and often deletes it from the server.

IMAP

Internet Message Access Protocol

Also for RECEIVING. Syncs with the server, allowing access from multiple devices.

POP3 vs. IMAP: Which is for you?

Scenario:

You use a laptop at work, a personal smartphone, and a tablet at home to check your university email. You want to see the same inbox, sent items, and folders on all devices.

Which protocol is better for this situation?

Answer: IMAP! It synchronizes all your actions across all devices by keeping the master copy of your email on the server.

3. FTP: The Heavy Lifter for Files 📂

FTP (File Transfer Protocol) is a specialized protocol designed to transfer computer files from one host to another over the internet.

Common uses include:

Uploading website files to a hosting server.
Downloading large software packages or data sets.
Sharing files that are too large for email attachments.

Chapter Summary & Key Takeaways ⚡

HTTP is the foundation of the World Wide Web, enabling communication between your browser and web servers. HTTPS adds a critical layer of security.
Email relies on a combination of protocols: SMTP is exclusively for sending, while POP3 or IMAP are used for receiving.
IMAP is the modern standard for email access across multiple devices, as it syncs with the server.
FTP is the go-to protocol for transferring files between computers, especially for web development and large file distribution.

Thank You!

This concludes our look at key internet application protocols.

Next Topic: Unit 8: Information Systems

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