Randy Bush’s 1993 whitepaper documents FidoNet, a store‑and‑forward email WAN built on dial‑up modems. Launched in 1984, the network grew to 20,000 nodes spanning six continental zones, each identified by a zone:net/node address. Originally written for MS‑DOS, implementations later appeared on UNIX, Apple //, Macintosh and other platforms, keeping the system alive across diverse hardware and continues to serve niche communities worldwide.

Efficiency drove protocol evolution. Early versions relied on an xmodem‑style 128‑byte packet scheme with ACK/NAK handshaking, a design still supported for its simplicity. Most modern nodes adopt optional zmodem‑based streaming, which eliminates ACKs and only NAKs on error, cutting telephone time dramatically compared with UUCP’s G protocol or SMTP traffic, resulting in lower phone bills for individual sysops.

The network’s hierarchical routing minimizes long‑distance calls: local nodes exchange mail directly, while a zone’s ‘inbound host’ aggregates external traffic, and designated zone‑gate nodes forward inter‑continental messages. Since 1991, experimental IP tunnels between zone gates have shifted bulk transfer to the Internet, saving operators thousands of dollars monthly. FidoNet’s blend of legacy BBS culture and modern gateways keeps it relevant for hobbyist communications.