What changes when you turn a Linux box into a router (patrickmccanna.net)

The article explains what Linux turns “on” when you repurpose a multi-homed host as a router or switch, focusing on seven configuration changes. It walks through enabling kernel IP forwarding, using a bridge to unify wired and wireless interfaces at Layer 2, and how Linux’s netfilter hook points (PREROUTING/INPUT/FORWARD/OUTPUT/POSTROUTING) are used for filtering, address translation, and related packet handling. It also covers practical components like sysctl for persistence and tools such as nftables/conntrack and hostapd for Wi‑Fi access-point bridging behavior.