Ubuntu
avahi package

  1. Bug #1230056
  2. Comment #19

Comment 19 for bug 1230056

Revision history for this message
Serhiy (xintx-ua) wrote : Re: ifdown waiting for 10 seconds before finishing in /etc/init/networking.conf during shutdown

It's something from avahi-daemon.
apt-get purge avahi-daemon solves the issue and reinstalling it makes it appear again.