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.
Nat
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Linux Networking Fundamentals -
Network Address Translation (NAT): A CCNA-Focused Guide A comprehensive, CCNA-focused guide to Network Address Translation — why NAT exists, the four address terms (inside local, inside global, outside local, outside global) made memorable, the three flavors (static NAT, dynamic NAT, and PAT/overload) with real Cisco IOS configuration and verification, the inside/outside interface gotcha that breaks every first attempt, how to troubleshoot with show ip nat translations and debug, and NAT's bigger-picture role: the security myths, broken end-to-end connectivity, carrier-grade NAT, NAT64, and how IPv6 changes the story. Built around exam topic 4.6 with commands you can lab.
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NAT Traversal: STUN, TURN, ICE, and How Peers Punch Through A deep technical look at how STUN, TURN, and ICE coordinate to let two devices behind NAT establish direct peer-to-peer connections — and what happens when they can't.
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CCNA: NAT and PAT — Network Address Translation in Depth Static NAT, dynamic NAT, and PAT explained from first principles — inside/outside local/global address terminology, full Cisco IOS configuration, NAT translation table interpretation, debug ip nat output, and troubleshooting every common failure mode.
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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.