How to configure Namecheap DynDNS in Fritzbox

dyndns refreshIn the previous article I have explained, how you can set up your domains, which are rented from Namecheap.com, for use with DynDNS (Dynamic DNS). In this article, we will focus on how to configure your Fritzbox, so that it always sends the current IP to the Namecheap DynDNS interface.
While this also possible through various clients for PC or MAC, I find the configuration with Fritzbox particularly attractive, because it is anyway running around the clock and thus no PC or MAC unnecessarily consumes more power.
(Who prefers a Raspberry Pi over a Fritzbox, should read this article here.)
Set up Namecheap DynDNS in the Fritzbox
Log into the webpanel of your Fritzbox. This should be normally accessible by navigating to http://fritz.box or http://192.168.178.1  in a browser of your choice.
Fritzbox Namecheap DynDNS