This is a quick guide on how to set up Namecheap Dynamic DNS on your FRITZ!Box.

For this guide, we’ll assume your domain is example.com, registered with Namecheap and that you’re running FRITZ!OS 7.20 or newer.

  1. In your FRITZ!Box web interface (usually http://fritz.box), sign in and go to Internet > Freigaben > DynDNS
  2. Check the box “DynDNS benutzen” to enable DynDNS
  3. In the provider dropdown (“DynDNS-Anbieter”) choose custom (“Benutzerdefiniert”)
  4. In the “Update-URL” enter the URL shown below
  5. In Domain name (“Domainname”) enter example.com (or your actual domain, rather)
  6. In Username (“Benutzername”) enter either @ if you want to use the root domain, or enter the subdomain to use
  7. In Password (“Kennwort”) enter the Namecheap “Dynamic DNS Password” (Can be found in the Namecheap Dashboard in your domain settings under “Advanced DNS”)

Namecheap Update-URL for FRITZ!Box:

https://dynamicdns.park-your-domain.com/update?host=<username>&domain=<domain>&password=<passwd>&ip=<ipaddr>

Note that this is for IPv4 only! Sadly Namecheap does not support Dynamic DNS with IPv6 yet.

Explanation on username / hostname

Namecheap wants both a domain name, and a hostname. The domain name (or zone) in this case would be example.com.

The “username” in FRITZ!Box is the hostname on Namecheap. If you want to use example.com as is, then you’ll need to use @ as username.
If you instead want to use subdomain.example.com as the hostname then you’ll enter “subdomain” into the username field.

Source on Update-URL

https://www.namecheap.com/support/knowledgebase/article.aspx/29/11/how-do-i-use-a-browser-to-dynamically-update-the-hosts-ip

That’s all there is to it! Happy hosting!