WGU D315 Network and Security Foundations 2026 Pre-Assessment – 190 Questions and Answers on OSI Model, TCP/IP, Firewalls, Cloud & Cybersecurity

This document contains approximately 190 WGU D315 Network and Security Foundations 2026 pre-assessment exam questions with verified answers covering OSI model layers, TCP/IP protocols, Ethernet standards, network topologies, routing, VLANs, wireless security, firewall technologies, cloud service models, virtualization, and cybersecurity principles . The content begins with foundational networking concepts such as OSI layer functions (Network layer for IP, Transport layer for TCP reliability), cable standards (CAT6a for 10Gbps), LAN vs WAN distinctions, and command-line tools including ping, traceroute, nslookup, netstat, ipconfig, and nmap. The document thoroughly explains Layer 2 and Layer 3 device operations (switches, routers, bridges, NICs), logical vs physical addressing (IP vs MAC), Ethernet switching behavior, VLAN segmentation, NAT and PAT functionality, and firewall types including packet-filtering, circuit-level, stateful inspection, and application-layer firewalls. Cybersecurity concepts include the CIA triad (confidentiality, integrity, availability), AAA (authentication, authorization, accounting), IDS vs IPS differences, common attack types (ARP poisoning, spoofing, phishing, buffer overflow, SQL injection, zero-day, denial-of-service), wireless encryption standards (WEP, WPA, WPA2, WPA3), and encryption methods (symmetric vs asymmetric). Cloud computing models are clearly distinguished (IaaS, PaaS, SaaS), as well as deployment types (public, private, community, hybrid). The document also reviews virtualization (Type 1 vs Type 2 hypervisors), VPN tunneling for secure transmission, data states (at rest, in transit), intrusion detection mechanisms, risk management strategies, and host hardening practices. The structured Q&A format closely aligns with WGU D315 Objective Assessment requirements and reinforces exam-ready terminology and applied troubleshooting scenarios. This document may concern: • WGU D315 Network and Security Foundations • WGU IT Foundations • Introduction to Networking • Cybersecurity Foundations • Cloud Computing Fundamentals • CompTIA Network+ Preparation It is particularly relevant for: • WGU IT students • Cybersecurity majors • Network administration students • Students preparing for the WGU D315 Objective Assessment • Entry-level IT certification candidates Keywords: WGU D315 network and security 2026 OSI model 7 layers physical data link network transport session presentation application TCP UDP transport layer protocols IP routing layer 3 CAT6a 10Gbps ethernet LAN WAN MAN network types VLAN segmentation switch trunk port NAT PAT firewall feature stateful inspection firewall application layer firewall CIA triad confidentiality integrity availability AAA authentication authorization accounting IDS vs IPS difference SQL injection buffer overflow phishing spoofing ARP poisoning wiretapping symmetric vs asymmetric encryption WEP WPA WPA2 WPA3 comparison IaaS PaaS SaaS cloud models Type 1 vs Type 2 hypervisor VPN secure tunneling