Networking Protocols

Networking for DevOps refers to the integration and management of network configurations, infrastructure, and communication between various systems and components in the context of DevOps practices.

The primary goal of networking is to enable devices to communicate with each other efficiently and securely over various types of networks, whether local or global.

Here are the key components and concepts in networking:

1. Devices in a Network:

• Computers, Servers, and Devices: These are the endpoints that send and receive data over the network.

• Routers: Direct network traffic by determining the best path for data to travel from one device to another.

• Switches: Connect devices within a local area network (LAN), allowing them to communicate with each other.

• Access Points: Enable wireless devices to connect to the network, often used in Wi-Fi networks.

2. Types of Networks:

• Local Area Network (LAN): A network that covers a small geographic area like an office, home, or building.

• Wide Area Network (WAN): A network that spans large geographical areas, often connecting multiple LANs across cities or countries.

• Metropolitan Area Network (MAN): A network that covers a city or large campus.

• Personal Area Network (PAN): A small network typically around a single person (e.g., Bluetooth connections).

3. Protocols:

• Transmission Control Protocol (TCP): Ensures reliable, ordered delivery of data packets between devices.

• Internet Protocol (IP): Provides addressing and routing so that data packets can find their way across networks.

• Hypertext Transfer Protocol (HTTP): The protocol used for transferring web pages on the internet.

• Simple Mail Transfer Protocol (SMTP): Used for sending emails between servers.

4. Routing and Switching:

• Routing: The process of directing data packets across different networks, often performed by routers.

• Switching: The process of forwarding data packets within a local network, often handled by network switches.

5. Network Security:

• Involves practices and technologies that protect data and devices from unauthorized access, misuse, or attacks. Common security measures include:

  • Firewalls: Control the incoming and outgoing network traffic based on security rules.

  • Encryption: Scrambles data so that it can't be read by unauthorized users.

  • Virtual Private Networks (VPNs): Provide secure connections over public networks

Mastering Networking Protocol : A Comprehensive guide to OSI and TCP/IP Models.

OSI Model

The OSI (Open Systems Interconnection) Model is a conceptual framework that standardizes the functions of a network into seven layers.

OSI Model – 7 Layers

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OSI Model Layer

1. Physical Layer

• Deals with the actual transmission of bits (0s and 1s) over a medium.

• Concerned with cables, signals, voltages, and connectors.

• Devices: Hubs, Repeaters, Network Cables, Fiber Optics.

2.Data Link Layer

• Establishes a direct, reliable link between two connected nodes.

• Handles MAC addresses, switches, and error detection (CRC).

• Divided into two sublayers:

  • LLC (Logical Link Control) – Error checking and flow control.

  • MAC (Media Access Control) – Defines how devices access the medium.

• Devices: Switches, Bridges, Network Interface Cards (NICs).

3.Network Layer

• Manages logical addressing (IP addresses) and routing packets.

• Uses routers to determine the best path for data.

• Supports fragmentation and reassembly of packets.

• Devices: Routers, Layer 3 Switches, Firewalls.

4.Transport Layer

• Ensures reliable or fast data delivery using:

  • TCP (Transmission Control Protocol) – Reliable, connection-oriented (e.g., web browsing, emails).

  • UDP (User Datagram Protocol) – Fast, connectionless (e.g., video streaming, VoIP).

• Handles error recovery, segmentation, and flow control.

5. Session Layer

• Establishes, maintains, and terminates communication sessions.

• Responsible for authentication and session checkpoints.

• Used in database access, remote procedure calls (RPCs).

6. Presentation Layer

• Translates data formats for applications (e.g., text, images, video).

• Handles encryption, decryption, and compression.

• Examples: JPEG, PNG, GIF (image formats), SSL/TLS (encryption).

7. Application Layer

• Interface for user applications to communicate over a network.

• Supports services like email, web browsing, file transfers.

• Examples: HTTP, HTTPS, FTP, SMTP, POP3, DNS, SNMP.

Why is the OSI Model Important?
✔ Helps troubleshoot network issues efficiently.
✔ Provides a universal standard for networking.
✔ Explains how different network devices communicate.

TCP/IP Model Breakdown

1. Network Access Layer (OSI Layers 1 & 2)

• Handles physical transmission of data (wired or wireless).

• Manages MAC addresses, Ethernet, Wi-Fi, and ARP (Address Resolution Protocol).

• Devices: Switches, Hubs, Network Interface Cards (NICs).

2. Internet Layer (OSI Layer 3)

• Routes data across different networks using IP addresses.

• Uses packet switching for efficient transmission.

• Key Protocols:

  • IP (Internet Protocol) – IPv4, IPv6

  • ICMP (Internet Control Message Protocol) – Error reporting (e.g., "ping" command)

  • ARP (Address Resolution Protocol) – Resolves IP ↔ MAC addresses

  • BGP, OSPF, RIP – Routing protocols for directing traffic

3.Transport Layer (OSI Layer 4)

• Ensures reliable (TCP) or fast (UDP) data transfer.

• Key Protocols:

  • TCP (Transmission Control Protocol) – Reliable, ordered, and error-checked delivery. Used in web browsing, emails, file transfers.

  • UDP (User Datagram Protocol) – Fast, connectionless. Used for video streaming, VoIP, DNS queries.

4. Application Layer (OSI Layers 5, 6, 7)

• Directly interacts with user applications.

• Defines protocols for communication, web browsing, email, and file transfer.

• Key Protocols:

  • HTTP/HTTPS – Web browsing

  • FTP/SFTP – File transfers

  • SMTP/POP3/IMAP – Email communication

  • DNS (Domain Name System) – Resolves domain names to IP addresses

  • SNMP (Simple Network Management Protocol) – Network monitoring

TCP/IP vs. OSI Model

Why is the TCP/IP Model Important?

✔ Foundation of the Internet – Used for all online communications.
✔ Practical & Scalable – Supports millions of connected devices.
✔ Interoperability – Works across different hardware and software.

Important Networking Protocols & Their Port Numbers

Here’s a list of essential networking protocols

Important Protocols & Port Numbers

1.Web & Internet Services

• HTTP – 80 (Unsecured web browsing)

• HTTPS – 443 (Secure web browsing via TLS/SSL)

• DNS – 53 (Domain name resolution)

• DHCP – 67 (Server), 68 (Client) (IP assignment)

2.Email Services

• SMTP – 25 (Sending emails)

• SMTP Secure (TLS/SSL) – 465, 587

• IMAP – 143 (Retrieving emails)

• IMAP Secure – 993

• POP3 – 110 (Older email retrieval)

• POP3 Secure – 995

3. Remote Access & Management

• SSH – 22 (Secure remote login)

• Telnet – 23 (Insecure remote login)

• RDP – 3389 (Windows remote desktop)

• VNC – 5900 (Remote desktop sharing)

• SNMP – 161, 162 (Network monitoring)

4. File Transfer & Sharing

• FTP – 20 (Data), 21 (Control)

• SFTP – 22 (Secure file transfer via SSH)

• SMB – 445 (Windows file sharing)

• NFS – 2049 (Linux/Unix file sharing)

5. Database Services

• MySQL – 3306

• PostgreSQL – 5432

• MS SQL Server – 1433

6.VPN & Security

• IPSec VPN – 500, 4500

• OpenVPN – 1194

• PPTP VPN – 1723