Network protocols
✅ What are Network Protocols?
A Network Protocol is a set of rules and standards that define how data is transmitted and received over a network. Protocols ensure that devices (computers, routers, servers, etc.) understand each other and communicate efficiently and securely.
🔑 Why Are Network Protocols Important?
Communication Rules
Define how data is packaged, transmitted, and received.
Interoperability
Allow devices from different manufacturers to communicate.
Error Handling
Ensure data is delivered correctly and in order.
Security
Provide encryption, authentication, and secure data transfer.
Efficiency
Manage bandwidth, speed, and resource use.
🌐 Types of Network Protocols (with Examples):
1. Communication Protocols (How data moves between devices)
HTTP (HyperText Transfer Protocol)
Web communication, browsing websites.
80
HTTPS (HTTP Secure)
Encrypted web communication.
443
FTP (File Transfer Protocol)
Transfer files between systems.
21
SFTP (Secure FTP)
Secure file transfer over SSH.
22
SMTP (Simple Mail Transfer Protocol)
Send emails.
25 (or 587 for secure)
POP3 (Post Office Protocol v3)
Retrieve emails (download and remove from server).
110 (or 995 for secure)
IMAP (Internet Message Access Protocol)
Manage emails directly on the server.
143 (or 993 for secure)
2. Network Management Protocols (Monitor & control devices)
SNMP (Simple Network Management Protocol)
Manage network devices.
161
ICMP (Internet Control Message Protocol)
Error reporting, diagnostics (e.g., ping).
N/A
3. Security Protocols
IPSec (Internet Protocol Security)
Encrypts IP traffic.
Various (depends on config)
SSL/TLS (Secure Sockets Layer/Transport Layer Security)
Secure web and app communication.
443 (HTTPS), others vary
SSH (Secure Shell)
Secure remote login.
22
4. Routing and Addressing Protocols (Direct traffic, assign addresses)
IP (Internet Protocol)
Addresses and routes packets.
N/A
TCP (Transmission Control Protocol)
Reliable connection-oriented communication.
N/A
UDP (User Datagram Protocol)
Fast connectionless communication.
N/A
DHCP (Dynamic Host Configuration Protocol)
Assign IP addresses automatically.
67, 68
DNS (Domain Name System)
Translate domain names to IP addresses.
53
ARP (Address Resolution Protocol)
Map IP addresses to MAC addresses.
N/A
5. Wireless & IoT Protocols
Wi-Fi (IEEE 802.11)
Wireless networking.
Bluetooth
Short-range communication between devices.
ZigBee
Low-power IoT communication.
NFC (Near Field Communication)
Very short-range communication (e.g., contactless payments).
🔗 Connection Protocol Examples (TCP vs UDP):
TCP
Connection-oriented
Yes
Web browsing (HTTP/HTTPS), Email (SMTP, IMAP)
UDP
Connectionless
No
Streaming, gaming, VoIP
📊 Layer-wise Network Protocols (Based on OSI Model):
Application (7)
HTTP, HTTPS, FTP, SMTP, IMAP, DNS
Presentation (6)
SSL/TLS, JPEG, MPEG
Session (5)
NetBIOS, PPTP
Transport (4)
TCP, UDP
Network (3)
IP, ICMP, IGMP
Data Link (2)
Ethernet, PPP, ARP
Physical (1)
Ethernet cables, Fiber optics, Wi-Fi
📡 Commonly Used Ports Table:
20, 21
FTP
File Transfer
22
SSH
Secure Shell
23
Telnet
Remote Login (Unsecure, deprecated)
25
SMTP
Email Sending
53
DNS
Domain Name Resolution
67, 68
DHCP
IP Address Assignment
80
HTTP
Web Browsing
110
POP3
Email Receiving
143
IMAP
Email Management
443
HTTPS
Secure Web Browsing
🧠 Why Understanding Protocols is Important?
Troubleshooting: Knowing which protocol is used helps in diagnosing network issues.
Security: Understanding which protocols are secure (e.g., HTTPS, SFTP, SSH).
Network Design: Proper protocol selection ensures efficient network operations.
Compliance: Certain protocols may be required for regulatory standards (e.g., encrypted communications).
✅ Summary of Key Protocol Categories:
Communication
HTTP, HTTPS, FTP, SMTP, IMAP
Management
SNMP, ICMP
Security
IPSec, SSL/TLS, SSH
Routing/Addressing
IP, TCP, UDP, DHCP, DNS, ARP
Wireless/IoT
Wi-Fi, Bluetooth, ZigBee, NFC
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