IT professional writing about cybersecurity, cloud & DevOps, automation, networking, and systems administration. Real-world guides for real-world problems.
Networking from Scratch (lesson 12, the capstone) — the six stages of a typical intrusion (initial access, foothold, lateral movement, privilege escalation, C2 + persistence, exfil + impact), the protocols attackers actually use, and the highest-leverage defence at each stage. Closes out the foundation pathway.
Networking from Scratch (lesson 11) — what a VPC actually is, why every cloud subnet is bound to one AZ, what really makes a subnet public or private, the four gateways (Internet, NAT, Peering, Transit), security groups vs NACLs, connecting to on-prem with VPN or dedicated interconnects, and the pets-vs-cattle mindset shift that changes how you think about IPs.
Networking from Scratch (lesson 10) — the middleboxes a packet traverses on the way to a real-world server (firewalls, load balancers, proxies, IDS/IPS, WAFs, VPN gateways), what each one does and where it sits, plus the internet hierarchy from IANA through RIRs and ISP tiers to IXPs and CDNs.
Networking from Scratch (lesson 9) — the seven OSI layers and four TCP/IP layers explained, the mapping between them, why both models exist, why engineers think in TCP/IP and name in OSI numbers, encapsulation in action, a layer-by-layer troubleshooting checklist, and the obligatory layer-8 joke.
Networking from Scratch (lesson 8) — the DNS hierarchy from root to authoritative, the recursive resolver path, TTL propagation, the records you will actually edit (A, AAAA, CNAME, MX, TXT, SRV), DNSSEC and DoH/DoT in plain English, and the dig and nslookup commands that turn DNS into something you can debug.
Networking from Scratch (lesson 7) — the two questions every transport protocol answers, what TCP guarantees that UDP doesnt, why DNS is UDP and HTTPS is TCP, and what QUIC adds that makes HTTP/3 faster than HTTP/2 over TCP. Plus a practical decision tree.
Networking from Scratch (lesson 6) — copper Ethernet categories with real distance limits, PoE class wattage, single-mode vs multi-mode fiber, the connectors and transceivers you will physically handle, the three Wi-Fi bands and why 2.4 GHz is a swamp, and how to recognise common physical-layer failures fast.
Networking from Scratch (lesson 5) — the difference between switches and routers in plain English, with the MAC table vs routing table side by side, a packet walked end-to-end through both, and why your home box is secretly two devices crammed into one chassis.
