Learn to troubleshoot network connectivity with a systematic 7-step method that works every time. Start at the physical layer and work up through IP, gateway, DNS, and firewall checks, with the exact commands to run.
Understand the IPv4 vs IPv6 differences with a 2026 perspective. Learn why IPv4 ran out, how IPv6 solves it, and what the March 2026 majority milestone on Google means for your network.
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.
What Is a MAC Address? How to Find and Look Up Yours TL;DR — Key Takeaways A MAC address is a unique 48-bit hardware identifier assigned to every network interface card (NIC) — it’s how devices identify each other on a local network. MAC addresses operate at Layer 2 (data link) and look like A4:83:E7:2F:5B:10 … 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