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IPv4
IPv4 — the original internet addressing system, still in use 40+ years later.
3 articles
networkingipv4isp
What is IPv4 exhaustion (and what's actually happening with it)?
We ran out of IPv4 addresses years ago — and the internet kept growing. Here's what 'exhaustion' actually means, why CGNAT and IPv6 buy us more time, and the surprisingly active market for buying IPv4 in 2026.
May 6, 20266 min read
networkingispipv4
What is CGNAT? Carrier-Grade NAT explained
If you can't host a server at home, port forwarding doesn't work, and your 'public' IP looks like 100.x.x.x — you're behind CGNAT. Here's what carrier-grade NAT is, why ISPs use it, and what to do about it.
May 6, 20266 min read
networkingadvancedipv4
How does NAT actually work? Network Address Translation in detail
NAT is the trick that lets dozens of devices in your home share a single public IP address. Here's exactly what NAT does to packets, the different NAT types, and why it caused decades of headaches for peer-to-peer apps.
May 6, 20266 min read