OpenDNS Fritzbox Howto

While I did some research on how getting this to work I saw many people trying this without success. Here is the definitive guide on how you use OpenDNS with your Fritzbox:
  1. Make sure your firmware is up-to-date
  2. Enable telnet
  3. Login over telnet and type "cd /var/flash/", "nvi ar7.cfg"
  4. Search for overwritedns1 and overwritedns2 (they appear two times each) using the "/" key and "n" (next search result).
  5. Press "i" to get into edit mode and enter the opendns server as noted in the opendns linux guide
  6. ESC brings you back to command mode. ":w" saves the file and ":q" closes the editor again.
  7. type "reboot" to restart the fritzbox
  8. Restart you networking and you browser. The OpenDNS Site now should tell you that you are using OpenDNS already. Now you can create an account, set it to dynamic DNS, add network and login to dnsomatic.
  9. Now login to using your browser and enter the following dynamic DNS settings: Update URL:<ipaddr>
    (This is the URL used by your fritzbox to send the new ip address to DNS-O-Matic)
    Domain name: Nothing here.
    User name: this should be your username.
    Password : your password
    password confirmation: you password again.
Now everything should work fine.


Unknown said…
Worked for me except instead of overwritedns1 and overwritedns2 I found overwrite_dns1 and overwrite_dns2 on my Fritz Box 7170.

Hint: after searching with "/overwrite_dns" and replacing it, just hit n in command mode to go to the next match.
Anonymous said…
If you already use another DynDNS provider and want to keep it, something like


could do the trick (untested).
TTalbot said…
If you read German, there is a somewhat simpler method outlined here:

Essentially, you can access the settings of the FritzBox by using the backup settings function on the web interface (something like "Settings / System / Save settings"). You can then change the corresponding entries in the downloaded text file (change "overwrite_dns1 =" to "overwrite_dns1 =" and "overwrite_dns2 =" to "overwrite_dns2 ="; CAREFUL, this must be done twice in the file!) and then restore the changed settings. One last note; you have to add "NoChecks=yes" at the start of the file, otherwise the FritzBox will notice you've made changes and think the file is corrupted and not perform the restore.
Unknown said…
Thanks for the instructions. This didn't work for me when using the LAN1 port as the WAN port. It may only apply to DNS profiles.

Luckily the current Fritzbox beta firmware allows you to specify services manually in the web interface which now works a treat.

Screenshot and instructions in my blog post:
Lstr said…
I discovered that the latest FritzBox firmware allows you to specify the DNS servers from the web interface. Thought people finding this post would appreciate the info.

Here is a link to the AVM FritzBox FAQ about setting DNS:
Configuring a different DNS server in the FRITZ!Box

In case the URL changes, the short answer is:
1. Open the FritzBox in your browser
2. Change to 'Expert mode'
3. Goto "Internet" > "Account Information" > "DNS Server"

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