Networking Core Protocols Explained : tryhackme
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Networking Core Protocols Explained: DNS, HTTP, FTP, SMTP, POP3 & IMAP
Understanding how the internet works behind the scenes is essential for anyone learning computer networking, cybersecurity, or IT fundamentals. In this article, we’ll explore the core networking protocols that power web browsing, file transfers, and email communication.
This guide is beginner-friendly and written in a way that’s suitable for Google AdSense monetization.
What Are Networking Core Protocols?
Networking protocols are rules that define how data is sent and received across a network. Without them, devices wouldn’t be able to communicate with each other effectively.
The most important core protocols include:
DNS
HTTP / HTTPS
FTP
SMTP
POP3
IMAP
DNS (Domain Name System)
DNS helps humans use easy-to-remember domain names instead of IP addresses.
For example:
google.com→142.250.x.x
Common DNS Record Types
A Record – Maps domain to IPv4 address
AAAA Record – Maps domain to IPv6 address
CNAME – Maps one domain to another
MX Record – Specifies email servers
Default Port: 53 (UDP/TCP)
HTTP and HTTPS (Web Access)
HTTP (Hypertext Transfer Protocol) is used when accessing websites.
HTTPS is the secure version, using encryption.
Common HTTP Methods
GET – Retrieve data
POST – Submit data
PUT – Update data
DELETE – Remove data
Ports Used:
HTTP → 80
HTTPS → 443
FTP (File Transfer Protocol)
FTP is designed for fast and efficient file transfers between a client and a server.
Common FTP Commands
USER– UsernamePASS– PasswordRETR– Download fileSTOR– Upload file
Default Port: 21 (TCP)
SMTP (Sending Emails)
SMTP is responsible for sending emails from a client to a mail server or between mail servers.
Important SMTP Commands
HELO / EHLO– Start sessionMAIL FROM– Sender addressRCPT TO– Receiver addressDATA– Start message content.– End of message
Default Port: 25 (TCP)
POP3 (Receiving Emails)
POP3 allows users to download emails from the mail server to a single device.
Key Features
Emails are usually deleted after download
Best for single-device usage
Default Port: 110 (TCP)
IMAP (Synchronizing Emails)
IMAP keeps emails stored on the server and syncs them across multiple devices.
Advantages of IMAP
Emails stay synchronized
Read, delete, and move actions are synced
Ideal for mobile and multi-device access
Default Port: 143 (TCP)
Default Port Numbers Summary
| Protocol | Transport | Default Port |
| TELNET | TCP | 23 |
| DNS | UDP/TCP | 53 |
| HTTP | TCP | 80 |
| HTTPS | TCP | 443 |
| FTP | TCP | 21 |
| SMTP | TCP | 25 |
| POP3 | TCP | 110 |
| IMAP | TCP | 143 |
Why Learning These Protocols Matters
Builds strong networking fundamentals
Essential for cybersecurity and ethical hacking
Helps understand real-world internet traffic
Makes troubleshooting much easier
Final Thoughts
Learning networking core protocols gives you a clear picture of how the internet truly works, beyond just clicking buttons on a screen. Whether you’re a student, IT professional, or cybersecurity enthusiast, mastering these basics is a huge step forward.
👉 Next step: Networking Secure Protocols to learn how these systems are protected.