A retained Linux pathname socket entry is separated from a crossed-out, closed listener by a large not-equal sign. In the source stream-socket fixture, connecting returns ECONNREFUSED; binding the same name returns EADDRINUSE.

Unix sockets provide local IPC with explicit naming and access rules

Unix domain sockets provide local interprocess communication without IP addresses, TCP ports, or an external network route. They still use kernel socket facilities, buffers, scheduling, and an application protocol. A pathname socket exposes a filesystem name, but Unix sockets can also be unnamed, and Linux supports abstract names. These naming forms have different access rules, so “a Unix socket is just a protected file” is incomplete. ...

November 28, 2026 · 5 min · XB Field Notes