My new provider gave a fritzbox, but not the passwords for VoIP and remote login… But I want to have them 🙂

First you need to get access to the OS, by enabling telnet
dial the following number on your phone (dect or conventional phone works; the iPhone app was not working for me)

#96*7*

connect to the box with your favorite telnet client (BSD telnet in this case, putty is probably fine as well)

telnet fritz.box

allcfgconv -c -o -

search for password (the easy way):

allcfgconv -c -o - | grep -E "(ddns|dyn_dns_name|account|username|passwd|emailnotify|user_email|account
name|passwd|jasonii|SMTPServeruser_email|box_id|boxusers|users|name|password)"

allcfgconv -C voip -c -o -

with some filters

allcfgconv -C voip -c -o - | grep -E "(voipcfg|name|authname|passwd|registrar|ua[1-9])"

<code> #96*8*