04 / CONNECTIONS

Computer
networking

Understand what happens between a device, a packet, and the thing you meant to reach.

IPV4 TOOL

Subnet mask calculator

Network: 192.168.1.0254 usable hosts
REFERENCE

Common ports

OSI MODEL

Seven layers, quickly

  1. Application HTTP, DNS
  2. Transport TCP, UDP
  3. Network IP, routing
  4. Link Ethernet, Wi-Fi
Packet capture simulatorWalk through a TCP handshake.
DNS resolution flowchartFrom URL to browser render.
Homelab plansVLANs, firewalls, and NAS storage.
IPv4 vs IPv6Exhaustion, headers, and routing.
VPN & tunnelingWireGuard, OpenVPN, and IPSec.
Troubleshooting toolkitPing, traceroute, nslookup, cable.