My router is probably malfunctioning. It's apparently sending requests for updates even though its IP has not changed.
I am incapable of fixing this issue and have thus disabled automatic DynDNS updates in my router. This should put a stop to _any_ update requests, legitimate or not.
Unfortunately, since I'm usually far away from my router for five days a week, and since there _is_ no computer behind that router which could update my DynDNS address for me, that also means I have to scan an IP range of 65k addresses _daily_ just to find my own router.
Ah well.
Greetings.