Networking Fundamentals and Troubleshooting Questions

Comprehensive coverage of core computer networking principles and the practical diagnostic and operational skills required to design, operate, and troubleshoot production systems. Fundamental concepts include the Open Systems Interconnection model layers, the Transmission Control Protocol and the Internet Protocol stack, the User Datagram Protocol, socket and port semantics, address notation and subnetting, Network Address Translation, Dynamic Host Configuration Protocol, and the Domain Name System resolution process. Infrastructure and architectural topics include switching and virtual local area networks, routing concepts and routing table behavior including Border Gateway Protocol basics, load balancing strategies and failure modes, firewall and access control, virtual private network technologies, and container and service network communication patterns. Diagnostic and tooling skills cover connectivity testing and path analysis, process and socket inspection, packet capture and analysis, and common command line tools and utilities used for network investigation. Performance and reliability topics include latency, bandwidth and throughput, packet loss, congestion and congestion control, connection pooling, timeout and retry strategies, and approaches to optimization. Observability, monitoring, and security practices include collecting and interpreting network metrics, logs, and traces, using packet capture tools for root cause analysis, and understanding how network issues surface in distributed applications. At senior levels expect discussion of network performance tuning, capacity planning, load balancer behavior at scale, and design decisions that affect system reliability and security.