ddupdate (service)

This service takes only the standard parameters start, stop and restart. The daemon is located under /usr/local/sbin/ddupdate and is written in Perl. It has support for DynDNS.org’s static and dynamic DNS, and uses HTTPS.

In order to “behave nicely” on DynDNS, ddupdate behaves like this:

1. after start it waits (10 minutes for dynamic, 1 hour for static IP)
2. it asks DynDNS’ DNS servers about the IP
3. if it doesn’t match, it will update
4. in a 1 minute cycle, it will (locally) check if the IP has changed and if it did, update

Finding out the local IP is done by looking at the routing table, especially the default route, so in certain special circumstances (like local NAT or multiple default routes) it may not do what is expected, but the typical cases are all automatically covered.

For configuration see dyndns.