inet-status.sh

#!/bin/bash

MODEM_IP="192.168.1.1"
ROUTER_IP="192.168.0.1"
INTERFACE="eth0"

# Check if we are running the script as root
if [[ $(id -u) -ne 0 ]]; then
  echo "Please execute this script as root."
  exit 1
fi

# Ping router 5 times to check if it's up; then ping modem 5 times to check if it's up.
# If any of these "tests" fail, we restart the interface.
if [[ ! $(ping -c 5 $ROUTER_IP 2>&1 /dev/null | echo $?) -eq 0 ]] && [[ ! $(ping -c 5 $MODEM_IP 2>&1 /dev/null | echo $?) -eq 0 ]]; then
  ifconfig $INTERFACE down
  ifconfig $INTERFACE up
fi