#!/bin/sh # This script is useful to check whether an interface is up and, # if not, it attempts to bring it back. This can be necessary # if your ISP provider causes occasional outages. # Some ISPs are known to termine connections when they reach # 24 hours to "prevent abuse". # Run this script through cron (every 5 minutes? your call) # and ensure that ifstate is located where it is defined below. # # NOTE: This script is just provided as an example. If you want this # feature you might be better off installing ifplugd which provides # similar functionality (but more featureful) out of the box. # TODO: # Improve it so it can find out (eg from /run/network/ifstate) # whether an interface was brought down # unexpectedly, or if a clean "ifdown" was issued. iface="$1" ifstate=/usr/local/sbin/ifstate if [ `$ifstate "$iface"` = DOWN ] then logger -s "Trying to bring $iface back up..." ifdown "$iface" ifup "$iface" [ `$ifstate "$iface"` = UP ] && logger -s "$iface now up again" fi exit 0