EDSC(4)

📦 version 12.2, in debian bookworm, debian trixie, ubuntu jammy, ubuntu noble, ubuntu questing, ubuntu resolute, ubuntu stonking

EDSC 💖 — the Ethernet discard network interface

okay bestie, pull up a chair because we're talking about edsc(4), a kernel interfaces manual page, and honestly? it's giving iconic. 🦋

✨ NAME ✨

edsc — Ethernet discard network interface 💅

🌸 SYNOPSIS 🌸

device edsc

that's it. that's the whole vibe. one line. slay. ✨

💖 DESCRIPTION 💖

so. the edsc interface is a software discard mechanism — like, it exists purely to throw stuff away — and you'd use it for performance analysis and software testing. it imitates an Ethernet device, which is the whole reason it can hang out with drivers like if_bridge(4) and vlan(4). besties fr fr. 🫶

and just like every other network interface out there, an edsc interface must have network addresses assigned, one for each address family you're planning to use it with. you can set or change those addresses with the SIOCSIFADDR ioctl(2) call, or with the ifconfig(8) utility if you'd rather not get your hands that dirty. 😌

each edsc interface gets created at runtime using interface cloning — no cap. the easiest way to do it is with the ifconfig(8) create command, or by setting the cloned_interfaces variable over in rc.conf(5). pick your fighter. 💅

🎀 SEE ALSO 🎀

go read them, they're all part of the lore. 📚✨

🦋 HISTORY 🦋

the edsc device was derived from the disc(4) device and first appeared in FreeBSD 6.3. and this very manpage? adapted from disc(4). it's giving family tree, it's giving legacy. 🌈

⚠️ CAVEATS ⚠️

okay listen, this is the part where we get serious for a sec. 🙈

since outgoing packets are just discarded by edsc, ARP requests stay unreplied. consequently, an IP packet cannot be sent via edsc until a static arp(4) entry is created for its next hop using arp(8). so like… nothing is going anywhere until you do that. periodt. 💀

also! initially an edsc interface has a zero link level address. if you need to change it, you can, with ifconfig(8) lladdr. just so you know. 🫶

and that's the whole page, bestie — this EDSC(4) from the Kernel Interfaces Manual was brought to you by Debian, dated March 25, 2007. oldie but a goodie. 💜✨ bye mwah 🎀

📦 where this page comes from