Automatically update Adfreetime.com IP address (for anti-region-blocking)

adfreetime_cron.sh

#!/bin/sh
# Automatically update Adfreetime.com IP address (for anti-region-blocking)
#
# Consider adding the following to /etc/dhcp/dhclient.conf: 
# prepend domain-name-servers 192.169.71.180, 208.110.81.50, 192.254.74.200; 
#
# Consider adding "ipv6.disable=1" to boot options in "/etc/default/grub", 
# Then run "update-grub" 
#

adfreetime_email="myemail@mydomain.com" # Set account name here

ipfile="/tmp/wanipaddr"
newip=$(dig +short myip.opendns.com @resolver1.opendns.com)

if [ -f "$ipfile" ]; then
    oldip=$(cat "$ipfile")
else
    oldip="0.0.0.0"
fi

if [ ! $oldip = $newip ]; then
    response=$(wget -qO- "http://login.adfreetime.com/cron.php?email=$adfreetime_email")
    echo "$response"
    if [ "$response" = "IP: $newip is activated!" ]; then
        echo "$newip" > "$ipfile" 
    else
        exit 1
    fi
else
    echo "IP: $newip has not changed."
fi
exit 0