Network · internals, protocols, ports, DNS, firewalls, home networking
Home & router · the admin page, Wi-Fi, port forwarding, chaining,
fixing it
OS · kernel and processes, Linux internals, Windows internals, host
security
Identity · Active Directory, Kerberos, authentication
Application · HTTP, OWASP, headers, secrets
Infra · nginx, reverse proxies, load balancing, TLS termination,
caching & CDN, capacity
Data · SQL, NoSQL, vector & graph stores, GraphQL, Kafka, MQTT,
Redis
Cloud · IAM, storage, metadata, containers
Cryptography · hashing vs encryption, keys, signatures, failures
Detection & IR · ATT&CK, the IR lifecycle, IOCs, common detections
Vuln Management · CVE/CVSS, KEV, prioritization, scan vs pentest
Threat Modeling · STRIDE, trust boundaries, attack trees, surface
Everything · mixed endless decks across all layers + fill-in-the-blank