- Firewall
- A security device or software function that inspects and filters network traffic according to a defined rule set to block unauthorized access.
- CCST
- Cisco Certified Support Technician, an entry-level Cisco certification designed as a first step toward the CCNA and aimed at technicians in help desk and IT support roles.
- OSI Model
- A seven-layer conceptual framework (Physical, Data Link, Network, Transport, Session, Presentation, Application) used to describe how data moves through a network.
- TCP/IP Model
- A four-layer networking model (Network Access, Internet, Transport, Application) that underlies real-world internet communication and maps to the OSI model's layers.
- LAN
- Local Area Network — a network confined to a small geographic area such as a single building or office.
- WAN
- Wide Area Network — a network that spans a large geographic area, typically connecting multiple LANs across cities or countries.
- MAC Address
- A Media Access Control address is a unique hardware identifier burned into a network interface card, used for Layer 2 frame delivery within a local network.
- IPv4
- Internet Protocol version 4, a 32-bit addressing scheme typically written in dotted-decimal notation (e.g., 192.168.1.1) that remains the dominant addressing method on most networks.
- IPv6
- Internet Protocol version 6, a 128-bit addressing scheme written in hexadecimal notation, designed to replace IPv4 and provide a vastly larger address space.
- Subnet Mask
- A 32-bit value paired with an IPv4 address that identifies which portion of the address represents the network and which represents the host.
- CIDR
- Classless Inter-Domain Routing — a method of allocating IP addresses and specifying subnet size using a slash notation (e.g., /24) instead of traditional class-based addressing.
- Default Gateway
- The router interface address a host uses to send traffic destined for any network outside its own local subnet.
- NAT
- Network Address Translation — a process that maps private internal IP addresses to a public IP address, allowing multiple devices to share one internet-facing address.
- DHCP
- Dynamic Host Configuration Protocol — a service that automatically assigns IP addressing information to devices joining a network.
- DNS
- Domain Name System — a distributed naming service that resolves human-readable domain names into IP addresses.
- VLAN
- Virtual Local Area Network — a logical grouping of switch ports that creates isolated broadcast domains on shared physical switching hardware.
- Switch
- A Layer 2 networking device that forwards frames between connected devices on the same network based on learned MAC addresses.
- Router
- A Layer 3 networking device that forwards packets between different networks based on destination IP addresses.
- Wireshark
- An open-source packet capture and protocol analysis application used to inspect network traffic in detail for troubleshooting and security analysis.
- WPA3
- Wi-Fi Protected Access 3 — the current generation of wireless security protocol, offering stronger encryption and handshake protection than its predecessor, WPA2.
- CIA Triad
- A foundational security model consisting of Confidentiality, Integrity, and Availability, used to guide the design and evaluation of secure systems.
- AAA
- Authentication, Authorization, and Accounting — a security framework for controlling and tracking who can access a network and what they are permitted to do.
- Single-Mode Fiber
- A fiber optic cable type with a narrow core that carries a single light path, typically using laser sources for long-distance, high-bandwidth connections.
- Traceroute
- A diagnostic utility that maps the sequence of routed hops a packet travels to reach a destination, helping isolate where a connectivity failure occurs.