ME(4)

📦 version 15.1, in freebsd 14.5, freebsd 15.1

💅 ME(4) — the encapsulating network device, bestie edition

okay so this is the manual page for me(4) from the Kernel Interfaces Manual and honestly? she's serving tunnel realness. let's get into it ✨

🦋 NAME 🦋

me — the encapsulating network device. yes that's her whole job. encapsulation. iconic.

🌸 SYNOPSIS 🌸

so there's two ways to get her in the building, and it depends on the vibe you want:

Option 1 — bake her straight into the kernel. drop this line in your kernel configuration file:

device me

Option 2 — module girl, loaded at boot time. put this in loader.conf(5) instead:

if_me_load="YES"

both valid, no cap. pick your lane 💖

✨ DESCRIPTION ✨

okay so the me network interface pseudo device encapsulates datagrams into IP. like, she takes your datagrams and wraps them up all cozy into IP. then those encapsulated datagrams get routed to a destination host, where they get decapsulated and routed onward to their final destination. it's giving mail-forwarding but for packets 🎀

also she doesn't just exist — me interfaces are dynamically created and destroyed with the ifconfig(8) create and destroy subcommands. main character energy: she appears when she's needed and dips when she's not.

this driver corresponds to RFC 2004, and the whole thing with this one is a shorter encapsulation. the way it works: the original IP header gets modified, and those modifications get inserted between the so-modified header and the original payload. and the outer header uses protocol number 55. periodt. 🔥

⭐ NOTES ⭐

heads up bestie, for correct operation the me device needs a route to the decapsulating host that does not run over the tunnel — because that would be a loop. and loops are not the vibe. 💀

🫶 SEE ALSO 🫶

go read them, iykyk 📚

👑 AUTHORS 👑

Andrey V. Elsukov <ae@FreeBSD.org> — thank you king, we love you for this one 💜

and that's the whole page! this particular rendering is from Debian, dated November 7, 2014 — so yeah, she's a vintage, and she still ate. mwah 💋🌈

📦 where this page comes from