Learning Objectives
- List and describe the functions of common network protocols
- Explain how network administration principles can be applied
- Define different network applications and how they can be secured
Common Network Protocols - TCP/IP
This introduces the Transmission Control Protocol/Internet Protocol (TCP/IP) suite, the foundation of most internet and local area network (LAN) communication. Let’s break it down:
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Protocols: Think of protocols as the rules of engagement for data transfer between devices. They dictate how data is formatted, addressed, and transmitted. Without these standardized rules, communication would be chaotic.
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TCP/IP Suite: This isn’t just one protocol; it’s a collection of protocols working together. The most prominent are:
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IP (Internet Protocol): Operates at the Network Layer (Layer 3 of the OSI model). Its primary function is addressing and routing data packets across networks. It provides the “address” (IP address) for each device.
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TCP (Transmission Control Protocol): Works at the Transport Layer (Layer 4). It’s responsible for establishing reliable connections, ensuring data arrives correctly and completely. Imagine it as the delivery service ensuring your package gets to its destination intact. TCP provides error checking and retransmission capabilities.
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Four-Layer Architecture: While often simplified to a two-layer model (IP and TCP), TCP/IP can be viewed as a four-layer stack: Network Interface (physical hardware), Internet (IP addressing and routing), Transport (TCP/UDP), and Application (user-facing protocols like HTTP, FTP).
Common Network Protocols - Other Protocols
This slide expands on the TCP/IP suite, introducing several other crucial protocols:
- ICMP (Internet Control Message Protocol): Used for error reporting and network diagnostics (e.g., ping). It allows devices to communicate about network problems.
- SNMP (Simple Network Management Protocol): Used for network management. Administrators use SNMP to monitor and configure network devices remotely. Security is paramount here; older versions are notoriously vulnerable.
- DNS (Domain Name System): Translates human-readable domain names (e.g., google.com) into machine-readable IP addresses. Essential for browsing the internet.
- File Transfer Protocols (FTP, TFTP) : Used for transferring files between computers. We’ll discuss their security implications and more secure alternatives shortly.
- NetBIOS: A legacy protocol mostly used by older Microsoft Windows systems for LAN communication. It’s generally considered insecure and should be disabled when possible.
- Telnet: Another legacy protocol for remote login. Extremely insecure as it transmits data in plain text; avoid using it. SSH is the secure replacement.
- IPv6: The next generation of IP addressing, designed to overcome the limitations of IPv4’s address space and improve security.