The macOS Network Stack - Sockets, pf, and Network Extensions #1008124

From BSD Sockets to Network Extensions, from pf rules to Bonjour discovery, the macOS network stack is deep — and mostly undocumented outside Apple's headers. This book walks every layer. BSD Sockets and Network.framework. URLSession and App Transport Security. TCP internals, IPv6, and DNS through mDNSResponder. The pf firewall and all four Network Extension types. Real commands, real output, and the reasoning behind each layer's design. For developers and administrators who need to know how traffic actually moves on a Mac.