To set up your DynDNS account used with INWX on a Fritz!Box, follow these steps:
Menu structure on the Fritz!Box: Internet -> Permit Access- > DynDNS
Use DynDNS: Activated
DynDNS provider: Custom
Domain name: Your DynDNS hostname
Username: Your DynDNS username
Password: Your DynDNS password
Note: The menu structure may vary depending on the Fritz!Box and software version used.