Use own letsencrypt ssl certs with Fritzbox

If you want to access the webui of the fritzbox underneath your own domain (static or dynamic dns) you can import the letsencrypt certs from your webserver (e.g. nginx in my case) to the fritzbox.

First Step: Collect and install cert

First login to your webserver and copy the certs for the fritzbox:

sudo cat /etc/letsencrypt/rsa-certs/privkey.pem /etc/letsencrypt/rsa-certs/fullchain.pem > ~/fritz.pem

Make sure you really paste privkey.pem AND fullchain.pem into the combined pem-file.

Then import the fritz.pem file underneath: Internet –> Freigaben –> Fritzbox-Dienste –> Zertifikat

Write down the IP and port at which the Fritzbox is reachable.

Second step: Configure Fritzbox

DNS-Rebind: Add your own domain e.g. to Heimnetz –> Netzwerk –> Netzwerkeinstellungen –> DNS-Rebind-Schutz to access the fritzbox underneath your own domain.

Enable your user to access the Fritz-Interface from the internet: System –> Fritzbox-User –> Edit User –> Allow internet access

Now you can enter the fritzbox with your own user from the internet. Make sure to use only safe passwords.