DISC(4)

💖 DISC(4) 💖

Kernel Interfaces Manual ✨

okay bestie, pull up a chair, we're talking about disc — the software discard network interface 🫶

🌸 NAME 🌸

disc — the software discard network interface, aka the "throw it in the void" queen 👑

✨ SYNOPSIS ✨

device disc

that's it. that's the whole vibe. 💅

🦋 DESCRIPTION 🦋

so like, the disc interface is a software discard mechanism — and honestly? iconic. it's built for performance analysis and/or software testing. it's the friend who just nods and lets you talk, no notes, no drama 🌈

and here's the thing, no cap: just like every other network interface, the discard interface must have network addresses assigned for each address family it's gonna be used with. yes, each one. every family gets its own addy, periodt 💅

those addresses can be set or changed with the SIOCSIFADDR ioctl(2) — that's the little syscall you hit up when you need to change an address, iykyk 🔥

okay so now the fun part 🎀 — every single disc interface gets created at runtime using interface cloning. it's giving very "build-a-bear but for network interfaces". and the easiest ways to do it?

• the ifconfig(8) create command — quick, cute, does the job ⭐
• or the cloned_interfaces variable in rc.conf(5) — for when you want it to happen automatically at boot, main character energy 👑

💜 SEE ALSO 💜

• inet(4)
• intro(4)

🧚 HISTORY 🧚

so the disc device lowkey appears to have been derived from the lo(4) device around the time of 4.4BSD — so it's old money, it's legacy, it's heritage 💖

and this very manpage was adapted from lo(4) and first appeared in FreeBSD 5.0. glow-up of the century fr fr ✨

🫶 reminder bestie: this page came to you from Debian, dated May 25, 2002. oldie but a goodie, mwah 💋