Grokking NAT and packet mangling in Linux

a year ago

All devices on a Wi-Fi network share the same public IPv4 address provided by the ISP.
IPv4 addresses are limited to ~4 billion unique addresses, leading to potential shortages.
IPv6 offers a vastly larger address space (2^128 addresses) but requires global adoption.
Network Address Translation (NAT) was introduced as a short-term solution to IPv4 limitations.
NAT allows multiple devices on a private network to share a single public IP address.
Port Address Translation (PAT) extends NAT by using different ports to identify devices.
Different types of NAT (e.g., Full Cone, Restricted Cone, Port-Restricted Cone, Symmetric) have varying restrictions.
NAT modifies packet headers, including IP addresses, ports, and checksums, to route traffic correctly.
Docker and other technologies rely on NAT for container networking.
NAT is not a perfect solution and has limitations, but IPv6 adoption is slow.

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