Script to get WAN ip address from Comcast SMCD3GNV router for use with ddclient.
My router software version: eMTA & DOCSIS Software Version: 3.1.5.3.3_NCS
Clone repository and copy script to /etc/ddclient/get_wan_ip (or wherever.)
Edit script and config as necessary (password and router ip address.)
Test script - no need to run as root and you should see your WAN ip address.
ddclient example setup using freedns.afraid.org:
use=cmd, cmd=/etc/ddclient/get_wan_ip
protocol=freedns
server=freedns.afraid.org
login=<your_login>
password=<your_password>
<your_ddns_hostname>