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API Course - Coggle Diagram

- - - - Examples of Network Services
      - Name Resolution
      - o Service: DNS (Domain Name System)
      - o Purpose: Converts human-readable names (like google.com) into IP addresses.
      - Addressing & Allocation
      - o Service: DHCP (Dynamic Host Configuration Protocol)
      - o Purpose: Automatically gives IP addresses and configuration (subnet, gateway, DNS) to devices.
      - File Sharing
      - o Service: FTP, NFS, SMB
      - o Purpose: Transfer or share files across computers.
      - Email Services
      - o Service: SMTP, IMAP, POP3
      - o Purpose: Send, receive, and manage email messages.
      - Web Services
      - o Service: HTTP / HTTPS
      - o Purpose: Deliver websites and web applications to users.
      - Remote Access
      - o Service: SSH, Telnet, RDP
      - o Purpose: Allow connecting and managing devices remotely.
      - Directory Services
      - o Service: LDAP, Active Directory
      - o Purpose: Centralized authentication and user management.
      - Time Synchronization
      - o Service: NTP (Network Time Protocol)
      - o Purpose: Keeps clocks in all devices synchronized.
  - - - 7 Layers of the OSI Model
      - (Top to Bottom)
      - 1. Application Layer (Layer 7)
      - Closest to the user.
      - Provides network services to applications.
      - Examples: HTTP, FTP, SMTP, DNS
      - 2. Presentation Layer (Layer 6)
      - Translates data between the application and the network.
      - Responsible for encryption, compression, encoding.
      - Examples: SSL/TLS (encryption), JPEG, GIF, ASCII, Unicode
      - 3. Session Layer (Layer 5)
      - Manages sessions (establishing, maintaining, ending communication).
      - Provides checkpoints and recovery.
      - Examples: RPC, NetBIOS
      - 4. Transport Layer (Layer 4)
      - Ensures reliable delivery of data between systems.
      - Handles segmentation, error detection, flow control.
      - Protocols: TCP (reliable), UDP (faster, no guarantee)
      - 5. Network Layer (Layer 3)
      - Handles logical addressing and routing of packets.
      - Determines the best path for data delivery.
      - Protocols: IP (IPv4/IPv6), ICMP, ARP, RIP, OSPF
      - 6. Data Link Layer (Layer 2)
      - Ensures error-free transfer of frames between two nodes in the same network.
      - Uses MAC addresses for communication.
      - Divided into:
        
        LLC (Logical Link Control)
        
        MAC (Media Access Control)
      - Examples: Ethernet, Wi-Fi (802.11)
      - 7. Physical Layer (Layer 1)
      - Lowest layer – deals with raw bit transmission over physical media.
      - Defines cables, connectors, voltages, frequencies.
      - Examples: Fiber optics, copper wires, radio signals
- - - - Encryption → Data exchanged is unreadable to attackers (confidentiality).
      - Integrity → Detects if data is altered during transmission.
      - Authentication → Ensures the server (and sometimes client) is who they claim to be.
  - - - SSL (Secure Sockets Layer)
        
        Older protocol developed by Netscape in the mid-1990s.
        
        First versions (SSL 2.0, SSL 3.0) provided encryption for web traffic.
    - - TLS (Transport Layer Security)
        Successor to SSL, standardized by the IETF.