Use Linode as DynDNS (DDNS) with your OpenWRT router (or Linux Box) for a cute domains ;)

linode_dns.sh

#!/bin/sh

DOMAIN_ID=$(uci get linode_dns.casa.domain_id)
RESOURCE_ID=$(uci get linode_dns.casa.resource_id)
API_KEY=$(uci get linode_dns.casa.api_key)

WGET="wget --no-check-certificate -qO - "

LAST_IP=$($WGET https://api.linode.com/?api_key=$API_KEY\&api_action=domain.resource.list\&DomainID=$DOMAIN_ID\&ResourceID=$RESOURCE_ID | sed -e 's/.*TARGET":"//' -e 's/".*$//')
CURRENT_IP=$($WGET http://checkip.dyndns.org | sed -e 's/.*Current IP Address: //' -e 's/<.*$//')

logger "Asigned: $LAST_IP - Current: $CURRENT_IP"

if [ "$CURRENT_IP" = "$LAST_IP" ]; then
    logger "No IP address change detected. Keeping $CURRENT_IP"
else
    RESPONSE=$($WGET https://api.linode.com/?api_key=$API_KEY\&api_action=domain.resource.update\&DomainID=$DOMAIN_ID\&ResourceID=$RESOURCE_ID\&Target=$CURRENT_IP)
    logger "Updated IP address to $CURRENT_IP"
fi