ifplugd(8)

📦
version 0.28 · 2 versions
, in debian bookworm, ubuntu jammy, ubuntu noble

okay so this page is ifplugd(8), and it lives in the System Manager's Manual section of the manual pages. no cap, it's a whole vibe. let's get into it 🫶

✨ NAME ✨

ifplugd — a link detection daemon for ethernet devices 🦋

✨ SYNOPSIS ✨

ifplugd [options]

✨ DESCRIPTION ✨

so basically ifplugd is a daemon that automatically configures your ethernet device when a cable gets plugged in, and automatically unconfigures it when the cable gets pulled. it's giving "i'll handle it, don't worry about it." 💅

this is especially iconic on laptops with on-board network adapters, because it will only configure the interface when a cable is really truly actually connected. not just because it's there. it's got standards. ✨

it uses your distribution's native ifup/ifdown programs, but bestie, you can configure it to do literally anything you want when the state of the interface changes. it can also ignore short unplugged whiles (-d option) or short plugged whiles (-u option) — so it's not out here overreacting to every little blip. main character emotional regulation fr fr. 🌸

ifplugd may also be used in "compatibility mode" by specifying -F on the command line. in that mode, ifplugd will treat network drivers that don't support link beat querying as always online. no cap, it just assumes the best. 🙈

✨ OPTIONS ✨

  • -a, --no-auto — do not enable the interface automatically (default: off)
  • -n, --no-daemon — do not daemonize (for debugging) (default: off)
  • -s, --no-syslog — do not use syslog, use stdout instead (for debugging) (default: off)
  • -b, --no-beep — do not beep (off), and this one overrides --no-beep-up and --no-beep-down
  • -U, --no-beep-up — do not beep on interface up (off)
  • -D, --no-beep-down — do not beep on interface down (off)
  • -f, --ignore-fail — ignore detection failure, retry instead. failure is treated as "no link". (default: off)
  • -F, --ignore-fail-positive — ignore detection failure, retry instead. failure is treated as "link detected". (default: off)
  • -i, --iface= IFACE — specify the ethernet interface (default: eth0)
  • -r, --run= EXEC — specify the program to execute when link status changes (default: /etc/ifplugd/ifplugd.action)
  • -I, --ignore-retval — don't exit on a nonzero return value from the program executed on link change. (default: off)
  • -t, --poll-time= SECS — specify poll time in seconds (default: 1)
  • -T, --poll-utime= USECS — specify poll time in microseconds, added to -t (default: 0)
  • -u, --delay-up= SECS — specify delay for configuring the interface (default: 0)
  • -d, --delay-down= SECS — specify delay for deconfiguring the interface (default: 5)
  • -m, --api-mode= MODE — force a specific link beat detection ioctl() API. possible values are auto, iff, wlan, ethtool, mii, and priv, for automatic detection, interface flag (IFF_RUNNING), wireless extension, SIOCETHTOOL, SIOCGMIIREG resp. SIOCPRIV. only the first character of the argument is relevant, and it's case insensitive. (default: auto)
  • -p, --no-startup — don't call the script to bring up the network on daemon start (default: off)
  • -q, --no-shutdown — don't call the script for network shutdown on daemon quit (default: off)
  • -w, --wait-on-fork — when daemonizing, wait until the background process finished with the initial link beat detection. when this is enabled, the parent process will return the link status on exit. 2 means link beat detected, 3 stands for link beat not detected, and everything else is an error.
  • -W, --wait-on-kill — when killing a running daemon (with -k), wait until the daemon died.
  • -x, --extra-arg= ARG — specify an extra argument to be passed to the action script.
  • -M, --monitor — don't fail when the network interface is not available, instead use NETLINK to monitor device availability. this is useful for PCMCIA devices and similar. 💜
  • -h, --help — show help
  • -k, --kill — kill a running daemon (specify -i to select the daemon instance to kill)
  • -c, --check-running — check if a daemon is running for a given network interface. sets the return value to 0 if a daemon is already running, or to 255 if not.
  • -v, --version — show version
  • -S, --supend — suspend a running daemon. the daemon will no longer check the link status until it is resumed (-R) again. (specify -i to select the daemon instance to suspend.)
  • -R, --resume — resume a suspended daemon. (specify -i to select the daemon instance to resume.)
  • -z, --info — request that a running daemon shall write its status information to syslog. (specify -i to select the daemon instance to send the request to.)
and yes bestie, --supend is spelled exactly like that in the original. i am not touching it. i respect it. 💅

✨ FILES ✨

  • /etc/default/ifplugd — this file is sourced by the init script /etc/init.d/ifplugd and contains the interface to be monitored and the options to be used. 📁
  • /etc/ifplugd/ifplugd.action — this is the script that will be called by the daemon whenever the state of the interface changes. it takes two arguments: the first is the interface name (eg. eth0), and the second is either "up" or "down".
  • /var/run/ifplugd.<iface>.pid — the pid file for ifplugd.

✨ ENVIRONMENT ✨

the action script will be called with two environment variables set:

  • IFPLUGD_PREVIOUS — the previous link status. either "up", "down", "error" or "disabled". the former values should be obvious, and the latter is set on daemon startup.
  • IFPLUGD_CURRENT — the current link status. see above for possible values.

✨ SIGNALS ✨

  • SIGINT, SIGTERM — ifplugd will quit, possibly running the shutdown script. this is issued by passing -k to ifplugd.
  • SIGQUIT — ifplugd will quit, and the shutdown script is never run.
  • SIGHUP — ifplugd will write its status information to syslog. this is issued by -z.
  • SIGUSR1 — ifplugd will go to suspend mode. (-S)
  • SIGUSR2 — ifplugd will resume from suspend mode. (-R)

✨ AUTHOR ✨

ifplugd was written by Lennart Poettering <mzvscyhtq (at) 0pointer (dot) de>. ifplugd is available at http://0pointer.de/lennart/projects/ifplugd/ 👑

✨ SEE ALSO ✨

ifplugd.conf(5), ifup(8), interfaces(5), ifconfig(8), ifplugstatus(8)

✨ COMMENTS ✨

this man page was written using xmltoman(1) by Oliver Kurth.

and that's the whole thing, bestie 🌈 so the footer of this page says it comes from Manuals, it's a User page, and it's titled ifplugd(8). go plug in a cable and let the daemon do its thing. slay. 💖✨🎀

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