From the TCP/IP model, IP addressing, CIDR, and NAT to network configuration, routing, DNS, firewalls, and troubleshooting — the concepts every developer needs and the Linux commands that put them to work.
Firewall
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Linux Networking Fundamentals -
pfSense and OPNsense: The Complete Home Lab Firewall Guide A comprehensive guide to pfSense and OPNsense — comparing the two platforms, choosing hardware, installing and configuring from scratch, setting up DHCP, DNS-over-TLS, firewall rules, NAT, VLANs, WireGuard, high availability with CARP, packages like pfBlockerNG and Suricata, and hardening your router/firewall for the home lab or small business.
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The Complete VPS Setup Guide: Security, Performance, and Quality of Life A comprehensive guide to setting up a VPS the right way — from choosing a vendor and hardening your first boot, to SSH mastery, firewall configuration, monitoring, backups, and quality-of-life improvements that make remote administration a pleasure.