Cloud & Infrastructure Topics
Cloud platform services, infrastructure architecture, Infrastructure as Code, environment provisioning, and infrastructure operations. Covers cloud service selection, infrastructure provisioning patterns, container orchestration (Kubernetes), multi-cloud and hybrid architectures, infrastructure cost optimization, and cloud platform operations. For CI/CD pipeline and deployment automation, see DevOps & Release Engineering. For cloud security implementation, see Security Engineering & Operations. For data infrastructure design, see Data Engineering & Analytics Infrastructure.
Cloud Networking and VPC Design
Designing networks inside a cloud provider: VPC/VNet topology, subnets, route tables, gateways, NAT, and peering, plus private connectivity through VPC endpoints and cloud load balancers. Covers segmentation, security groups and network ACLs, hybrid connectivity to on-premises data centers over VPN or dedicated links like Direct Connect and ExpressRoute, IP address planning across many VPCs and accounts, and how cloud network design differs from traditional data-center networking.
Active Directory Architecture and Management
Designing, operating and recovering Active Directory Domain Services and the directory estate around it. Covers logical and physical structure (forests, trees, domains, OUs, trusts, schema extension, FSMO roles, Global Catalog, RODCs), sites and replication topology, domain controller placement, promotion, upgrade and functional levels, DC locator and AD-integrated DNS, domain join, Kerberos and NTLM authentication including SPNs and delegation, token size and SID history, LDAP binds and query tuning, Group Policy design, processing order, filtering, deployment and troubleshooting, user, group, computer and service account management including PowerShell account scripting and account lockout investigation, delegation of control and tiered administration, fine-grained password policy, backup, authoritative restore, forest recovery and USN rollback, AD hardening against Kerberoasting, DCSync and Golden Ticket attacks, forest migration, and hybrid identity with Microsoft Entra ID (Microsoft Entra Connect, Cloud Sync, password hash sync, pass-through authentication, federation, password writeback). Questions are asked from the directory administrator's and architect's seat. Platform-neutral identity protocols and lifecycle design, Windows file-server administration (shares, NTFS permissions, profiles), Linux directory integration, and generic DNS and DHCP service operations are covered elsewhere.
Networking Fundamentals and Protocols
The core model of how networks move data: the OSI and TCP/IP layers, the Internet Protocol suite, transport protocols (TCP versus UDP), encapsulation, and TCP behavior including congestion control. Covers the protocol foundations every networking and infrastructure discussion builds on, from link layer through transport. The conceptual bedrock beneath addressing, routing, and switching.
IP Addressing and Subnetting
Working with IP address space: IPv4 and IPv6 addressing, subnet masks and CIDR notation (including why classful addressing was abandoned), VLSM calculation, route summarization from an addressing standpoint, private (RFC1918), ULA, link-local (including 169.254 self-assigned) and public ranges, and multicast address ranges. Covers designing hierarchical addressing schemes for sites, VLANs, security zones, DMZs and data centers, laying out prefixes so ACL and QoS policy stays compact, NAT and CGNAT for address conservation, static versus DHCP-assigned addressing, IPAM practice, renumbering after mergers or overlaps, and IPv4-to-IPv6 transition (dual-stack, tunneling, NAT64/DNS64). Boundary: routing protocol operation, cloud VPC topology, DNS and DHCP service operation, and firewall design are covered elsewhere.
Infrastructure as Code and Automation
Defining, provisioning, and automating infrastructure programmatically. Covers declarative IaC with Terraform and comparable tools like CloudFormation (resource and provider model, state management and remote backends, module design and reuse, workspaces, drift detection, and safe plan/apply workflows), plus the broader automation discipline: provisioning pipelines, golden-image and machine-image building, scripting glue, self-service platforms, and end-to-end environment stand-up. The authoring, lifecycle, and automation of infrastructure code that reduces manual toil across provisioning workflows.
Google Cloud Platform Services and Architecture
Google Cloud Platform's core services and architecture: Compute Engine, Cloud Run, GKE, Cloud Storage, VPC, managed databases (Cloud SQL, Spanner, Firestore, Bigtable), and BigQuery-adjacent data services. Covers GCP service selection, networking, IAM and security specifics, cost and quota management, and reference patterns for building on the platform. For provider-agnostic compute, storage, or networking concepts, see the cross-cloud entries.
DNS, DHCP, and Name Resolution
How names and addresses are served and kept working on a network. DNS: resolution flow (stub, recursive, authoritative, root/TLD referrals), host-side resolver configuration and why one machine or process resolves differently from another, record types and their pitfalls (including apex aliasing, MX, SRV and CAA use), zones, delegation and glue, caching, TTL and negative caching, split-horizon and private zones, reverse DNS, zone transfers (AXFR/IXFR, TSIG), DNSSEC and key rollover, resolver and authoritative fleet design, forwarding versus running recursion, encrypted DNS (DoH/DoT), truncation, TCP fallback and EDNS, DNS-layer attacks (cache poisoning, amplification, spoofed-source floods), DNS health from the user's point of view, and DNS changes, mail and registrar migrations and outages. DHCP: address assignment and leases, scopes and sizing, reservations, relay across VLANs including relay agent information (option 82), redundancy and failover, and rogue or exhausted-scope failures. Includes diagnosing resolution failures that masquerade as wider outages. Excludes the layered network fault-isolation method and general packet capture, Active Directory-integrated DNS on domain controllers, DNS-based service registries for microservices, load-balancing algorithm design and global traffic steering, incident-command process and SLO or error-budget design, and generic scripting or infrastructure-as-code tooling.
Switching, VLANs, and Layer 2 Segmentation
Layer 2 switching and segmentation: MAC learning, aging and forwarding (including unknown-unicast flooding and cut-through versus store-and-forward), VLAN design and 802.1Q trunking (tag format, native VLAN, DTP trunk negotiation, VTP, voice VLAN, private VLANs, Q-in-Q), spanning tree (STP, RSTP, MST and edge protection such as PortFast, BPDU guard and root guard), EtherChannel/LACP and MLAG, multicast handling with IGMP snooping, and the hand-off between layer 2 and layer 3 (SVIs, router-on-a-stick, routed ports). Covers access and trunk port configuration and verification, switch-level fault diagnosis (trunk and native VLAN mismatches, MAC flapping, broadcast storms, bundles that will not form), campus, small-office and data-centre VLAN plans, and migrating or renumbering VLANs with minimal downtime. Boundary: attack and defense mechanics (MAC flooding, DHCP snooping, ARP inspection, VLAN hopping), routing protocol configuration, VXLAN/EVPN overlays, fabric and whole-campus topology choice, device automation, and the generic layered troubleshooting method are covered elsewhere.
Cloud Service and Deployment Models
The foundational service models (IaaS, PaaS, SaaS, FaaS) and deployment models (public, private, and hybrid cloud) and when each is appropriate. Covers the shared-responsibility boundary, the core value proposition of cloud versus on-premises, how service-model choice shifts operational ownership, vendor lock-in risks and mitigation, and when a single-cloud, multi-cloud, or hybrid-cloud strategy is the better choice. The conceptual entry point before any provider-specific or architectural depth.