This is how I configured my FRITZ!Box Fon WLAN 7170. Using this configuration, I do not need to configure the various PCs in my home network. My phone is connected to the Fritz!Box. You should only do this if you are comfortable with unix commands like cd and vi.
1. Activate Telnet using the telephone with #96*7*
2. In the command prompt (cmd) enter telnet fritz.box
3. If a password is requested, enter your Fritz!Box password
4. Enter "cd /var/flash"
5. Enter "nvi ar7.cfg"
6. Edit the overwrite_dns1 and overwrite_dns2 entries to use the openDNS IP addresses instead of 0.0.0.0
overwrite_dns1 = 208.67.222.222;
overwrite_dns2 = 208.67.220.220;
Save your changes.
7. Enter "reboot" to reboot the Fritz!Box
8. Point your browser to http://www.opendns.com/
9. Create an account, a network and activate dynamic DNS for your account
10. Logon to www.dnsomatic.com once
11. Point your browser at http://fritz.box
12. Goto Einstellungen | Internet | Freigaben | Dynamic DNS
Dynamic DNS-Anbieter: Benutzerdefiniert
Update URL: updates.dnsomatic.com/nic/update?myip=
Domain: all.dnsomatic.com
User: Your openDNS user
Password: Your openDNS password
Click on Übernehmen
12. Deactivate Telnet using the telephone with #96*8*
para repor a situação devemos colocar novamente os dns a 0.0.0.0;