Network administration and security tutorials
BGP route hijacks remain a real operational threat in 2026, and Route Origin Validation (RPKI) is the only widely-deployed defense. This complete guide walks through what RPKI actually does, how to publish ROAs for your prefixes, how to deploy a validator (Routinator or NLnet Labs Krill), and how to configure your edge routers to actually drop invalid announcements — without dropping your customer traffic....
iptables is deprecated, nftables is the new default, and most production rulesets are still iptables converted to nft syntax. Here is how to design a real nftables ruleset that is fast, atomic, dual-stack and easy to read....
Understand how DNS works from the ground up. This guide explains domain resolution, record types, caching, troubleshooting with dig and nslookup, and DNS security basics....
Set up a DNS server with BIND on Linux. Covers installation, zone files, forward and reverse lookups, DNSSEC, and troubleshooting....
Master essential Linux networking commands for 2026. Complete reference covering ip, ping, dig, ss, traceroute, tcpdump, firewall management, and systematic troubleshooting workflows....
The definitive 2026 guide to nftables, the modern Linux firewall. Installation, basic rules, advanced NAT, sets, maps, rate limiting, Docker, dual-stack IPv4/IPv6, iptables migration, and production hardening. Free 20-page PDF cheat sheet included....
Master WireGuard VPN from installation to production. Learn key generation, server/client configuration, site-to-site tunnels, mesh networks, firewall setup, performance tuning, and security best practices in this comprehensive 2026 guide....
Set up a WireGuard VPN on Linux step by step. Learn key generation, server and client configuration, firewall rules, and connecting multiple peers securely....
Learn a systematic approach to Linux network troubleshooting using essential tools like ping, traceroute, ss, tcpdump, and dig. This hands-on guide walks you through diagnosing connectivity issues, DNS problems, firewall rules, and performance bottlenecks....