Networking Concepts

Networking Concepts

  • Networking refers to the interconnection of computers for sharing resources and data.

Ethernet Network

  • Medium: Uses twisted pair copper cables and optical fiber.
  • Speed: Ranges from 100 MB/s to 10 GB/s. Twisted pair supports 64KB.
  • Topology: Implements a star topology.
  • Protocol: Uses CSMA/CD (Carrier Sense Multiple Access with Collision Detection) to manage data transmission.

Internet and Transport Protocols

  1. Ethernet Network: Standard for local area networks (LAN).
  2. TCP/IP (Transmission Control Protocol/Internet Protocol): Standard model for internet communications.
  3. UDP (User Datagram Protocol): Offers faster transmissions with no error checking.
  4. TCP (Transmission Control Protocol): Ensures reliable, ordered transmission of data.
  5. IP (Internet Protocol): Handles addressing and routing data between hosts.

Network Routing

  • Routing Tables: Lists of networks used by routers to direct traffic.
  • Interior vs. Exterior Routing: Interior routing occurs within an organization, while exterior routing occurs between organizations.
  • Secure Routing Protocols: Minimize risks of sabotage and errors in routing information.

Monitoring Network Traffic

  • Tools: Wireshark and nmap can be used to analyze and scan network traffic.
  • Traffic Inspection: Real-time monitoring of network packets to troubleshoot and analyze traffic flow.
  • Packet Structure: Data is sent in packets with headers containing important information like source and destination IP addresses.

Network Services

  • Domain Name System (DNS): Translates human-friendly domain names into IP addresses.
  • Dynamic Host Configuration Protocol (DHCP): Automatically assigns IP addresses to devices on a network.
  • File Transfer Protocol (FTP): Used for relocating files between hosts.

Security and Attacks in Networking

  • Common Attacks:
    • Denial of Service (DoS): Flooding a network to make it unavailable.
    • Cache Poisoning: Corrupts DNS cache to redirect users.
    • SYN Flood: Exploits TCP handshake to consume resources.
  • Defense Strategies:
    • Use of firewalls and gateways to secure networks.
    • Implementation of encryption techniques.

Summary of Key Ethernet Features

  • Collisions: Two hosts transmitting simultaneously lead to collisions, requiring a retransmit.
  • Ethernet Packet Structure: Header contains MAC address, packet type, data field, and CRC for error checking.
  • MAC Address and IP Address: Unique identifiers necessary for network communication.

Additional Concepts

  • Port Numbers: Used in TCP and UDP for directing traffic to specific applications (e.g., 80 for HTTP, 443 for HTTPS).
  • IP Address Format: Typically in dotted decimal, with 32-bit IPv4 becoming scarce; IPv6 is the next iteration with longer addresses.
  • Network Address Translation (NAT): Converts private addresses to public addresses to enable internet connectivity.