DynDNS.org + Bash + Router == A tiny bit safer.

Pondering how to lock down a few bits to just an IP or two I hacked together this awful bit of bash:

#!/bin/bash
function valid_ip()
{
    local  ip=$1
    local  stat=1

    if [[ $ip =~ ^[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}\.[0-9]{1,3}$ ]]; then
        OIFS=$IFS
        IFS='.'
        ip=($ip)
        IFS=$OIFS
        [[ ${ip[0]} -le 255 && ${ip[1]} -le 255 \
            && ${ip[2]} -le 255 && ${ip[3]} -le 255 ]]
        stat=$?
    fi
    return $stat
}

HOME_IP=`host dyndnsname.dyndns-home.com|awk '{print $4};'`

if valid_ip $HOME_IP; then
	OLD_IP=`grep HOME_IP /home/user/public_html/blog/wp-admin/.htaccess|awk '{print $3}'`;
	if [ $OLD_IP != $HOME_IP ]; then
		sed -i -e "s/ [0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\}\.[0-9]\{1,3\} #HOME_IP/ $HOME_IP #HOME_IP/" \
			 /home/user/public_html/blog/wp-admin/.htaccess
		echo "DNS Changed to $HOME_IP from $OLD_IP"
	fi
fi

exit

So if you have a locked down .htaccess something like:

Satisfy any
order deny,allow
allow from 12.12.12.12 #HOME_IP
deny from all

The above script will update it. Bung it in cron and hey presto. Most routers have options to update dyndns and other services to ensure your IP is current generic diovan.