% systemctl status net-auto-wired.service
net-auto-wired.service - Provides automatic netcfg wired connection
Loaded: loaded
(/usr/lib/systemd/system/net-auto-wired.service; enabled)
Active: failed (Result: exit-code) since Tue, 08 May 2012
21:19:30 +0800; 8s ago
Process: 28629 ExecStart=/usr/sbin/ifplugd -i
$WIRED_INTERFACE -r /etc/ifplugd/netcfg.action -fIw -d10 (code=exited,
status=3)
CGroup: name=systemd:/system/net-auto-wired.service

I do in fact get exit code 3 when running the ExecStart line by hand,
and removing -w seems to take care of it. -w seems to wait for link
detection, but it seems anything it returns (in the above case I got 3
because I'm currently on wireless and have no LAN to test it on) would
cause an error? The rc.d script doesn't seem to use -w, so I'm
wondering why that was inserted for the service file.