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.
Ipv4
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Network Address Translation (NAT): A CCNA-Focused Guide -
IPv6 Basics: Why We Need It, How It Differs from IPv4, and What It Unlocks IPv6 quietly crossed 50% of Google's traffic in early 2026. A from-scratch explanation of why the internet ran out of IPv4 addresses, how IPv6 actually differs beyond just being bigger, and the genuinely useful things a 128-bit address space makes possible.
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Subnetting Explained: Why Subnet Masks Aren't Just 255s and 0s A from-intuition walk through subnetting, and a direct answer to the question every beginner eventually asks: would you ever use a subnet mask octet that isn't 255 or 0? Yes — constantly — and here is exactly when and why.
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CCNA: IPv4 Addressing and Subnetting A complete guide to IPv4 addressing and subnetting for CCNA — binary conversion, CIDR, subnet masks, the magic number method that works under exam pressure, VLSM design, and route summarization with fully worked examples.
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CCNA: IPv4 Routing Fundamentals How routers make forwarding decisions, the routing table in depth, administrative distance, static routes with next-hop vs exit-interface, default routes, recursive lookups, and connected/local routes — with full Cisco IOS CLI examples.
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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.