How does DNS actually work? Walk through the full resolution chain from browser cache to authoritative nameservers. You’ll also see modern encryption protocols (DoH, DoT, DoQ) and exactly what changed in 2026.
Understand public vs private IP addresses, how NAT bridges them, and the often-missed fourth range (RFC 6598’s 100.64.0.0/10) that ISPs now use for carrier-grade NAT on mobile and satellite networks.
Master the common network ports every IT pro should know, organized by category for TCP and UDP. Includes port security, how to check open ports, and why HTTP/3 now puts HTTPS on UDP 443.
TL;DR — The Short Version Subnetting divides a large network into smaller, more manageable segments for better security, performance, and organization. A subnet mask tells you which bits of an IP address identify the network and which identify individual hosts. CIDR notation (like /24) is shorthand for how many bits belong to the network portion … Read more
Wondering what reverse DNS is and why your emails are bouncing? PTR records and FCrDNS now decide whether Gmail, Outlook, and Yahoo accept your mail. Here is what changed in 2024-2025 and how to fix it.
Understand every DNS record type you’ll actually use, from A and MX to TXT and NS, with real examples. Plus the new HTTPS and SVCB records that speed up HTTP/3 and enable Encrypted Client Hello.
TL;DR — Key Takeaways A MAC address is a unique 48-bit hardware identifier for a network interface. It is how devices find each other on a local network. MAC addresses work at Layer 2 and look like A4:83:E7:2F:5B:10. That is six hex pairs split by colons or hyphens. Find yours in system settings or with … Read more
TL;DR — Key Takeaways Your public IP address is the address the rest of the internet sees when your devices connect. It is assigned by your ISP, not by you. The fastest way to find it is to use a web-based IP lookup tool. One click. You can also check your IP from the command … Read more