Networking

A short reference on RFCs — what Request for Comments documents are, who publishes them, why the name is a 50-year-old misnomer, what MUST and SHOULD legally mean, and which numbers are worth recognizing on sight.

A short reference on ICMP — the internet's control channel, why it has no ports, the message types behind ping and traceroute, what breaks when firewalls drop it, and why blocking all of it black-holes your own connections.

A reverse proxy is the single front door that sits in front of your backends — clients only ever talk to it. This explains routing, TLS termination, load balancing, caching, and how it differs from a forward proxy.

A short reference on Transport Layer Security — what the padlock actually guarantees, how the certificate chain of trust works, and how Let's Encrypt and the ACME protocol automate issuing the certificate that proves you own a domain.

A short reference on virtual private networks — what the encrypted tunnel actually is, the difference between privacy-product VPNs and infrastructure VPNs, and how WireGuard builds one with keys, peers, and a single UDP port.

A short reference on Network Address Translation — why it exists, how the translation table is built from outbound connections, why unsolicited inbound traffic is dropped, and how carrier-grade NAT takes away your public IP entirely.

A short reference on dynamic vs static IPs — what each means, how DHCP leases work, when each is the right choice for clients and servers, and where the boundary between them gets blurry in cloud and home networks.

A short comparison of IPv4 and IPv6 — address size, format, why IPv6 was designed in 1998, what changed beyond the obvious 32-vs-128-bit width, and why the migration is still going thirty years later.

A short reference on anycast — one IP address announced from many locations, how routing picks the nearest one, why CDNs and DNS root servers use it, and where the edge cases bite.

A short reference on the Domain Name System — the hierarchy, common record types, how a recursive resolver actually looks up a name, and the caching that keeps the whole thing usable.

A short reference on traceroute — what it actually does with TTL, when to reach for it, the differences between traceroute, tracert, and mtr, and how to read the output without misinterpreting the hops.

A short reference on Classless Inter-Domain Routing notation — what `/N` means, how the prefix and host bits divide, why it replaced the A/B/C class system in 1993, and the common sizes you see in real-world networks.

A short reference on subnets — what they actually are, how the mask separates network bits from host bits, why subnetting exists, and how to think about sizing one.