Dynamic DNS Updater

The Problem

The Cisco implementation for Dynamic DNS updating is broken in two ways that I've found:

• Firstly, there's Cisco Bug ID CSCtx50249, which truncates the password in the URL to 15 characters. DynDNS providers that generate a key for your domain seem to prefer 16 characters.
• On the 830-series of routers, the DynDNS updater does not do HTTP/1.1 requests to the server, but instead an HTTP/1.0 request. This is a problem with EasyDNS, as their update server is on a virtual host, which requires an HTTP/1.1 request in order to present the user with the correct website. This doesn't appear to be an issue on the 1800 or 870-series.

The Solution

Use Cisco's IP SLA functionality to generate the proper request.

ip sla 1

http raw http://api.cp.easydns.com
http-raw-request
 GET /dyn/tomato.php?hostname=dyn.example.ca HTTP/1.1\r\n
 Host: api.cp.easydns.com\r\n
 Authorization: Basic dXNlcm5hbWU6cGFzc3dvcmQ=\r\n
 \r\n
 end
 exit
frequency 3600

ip sla schedule 1 life forever start-time now