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Remotely Connecting to your FritzBox using Jitsi

September 9th, 2015 by ‐ No Comments

telephone pictogramThere are many complaints about VoIP service being offered to you as the primary voice service by your telco. It usually means that the Ethernet hub on the DSL router becomes the handover point (i.e. you don’t fully control your router), the service availability is often only 98.9% (i.e. 4 days of no service per year) or even worse. For ye olde analogue phone, the usual service availability was 99.99% (53 minutes of no service per year). But, there is one clear advantage: you can install a SIP softphone and register your laptop or smartphone as a phone and place and receive calls via your home phone wherever you have WiFi or mobile data service. I have a FritzBox 7360 from my ISP glowing along, and hence the instructions how to set this up are for this model. If you have another FritzBox model with telephony function, the setup will be quite similar. For any other DSL router makes, you’ll have to check out the instructions for your device to find the corresponding settings. Without further ado, here are the instructions. 

  1. First, you will need a way of connecting to your DSL router from outside. Since your ISP can, and will, change the router’s IP address at (his) will, you will need a symbolic name. If you own a FritzBox, the manufacturer AVM (language switch at the bottom of the page) provide the MyFRITZ service for their devices. If you own a device from a different manufacturer, you will have to choose among one of the many free services. Simply search for “dynamic DNS” and take your pick.
  2. Create a new phone device in the settings of your FritzBox as described in step “2 Configuring a telephone in the FRITZ!Box” in this guide. Be sure to also enable the new device for access from the Internet as described in step “4 Configuring the telephone for registration from the Internet” of the same guide. Choose your password well (letters,, numbers, upper and lower case, etc.). Hint: the first phone device (often an analogue or DECT phone) is assigned the number 620. Further devices are assigned 621, 622, and so forth.
  3. Now your FritzBox is all set up, and it’s time to think about the softphone to use. On Mac OS X, I recommend Jitsi. On iOS, I recommend Groundwire. I searched for long, and tried out many, but none of the others really worked for me.
  4. The remaining instructions are for setting up Jitsi, but you should easily be able to infer the settings for your client, too. To start, launch Jitsi, open its preferences, click on the accounts tab, and click “add” below the still empty list. In the “add new account” dialogue that pops up, select SIP as the account type from the drop-down, and click on advanced at the bottom. Now you get a big dialogue titled “account registration wizard” with five tabs. Fill in your credentials as show below.
    Login credential settings

    Login credential settings (click to enlarge)

    Your SIP id is the internal number of your new phone device from step 2 (we use 622 for this example), followed by “@”, followed by the hostname for your DSL router obtained in step 1. For the MyFRITZ service, this will be gibberish.myfritz.net. Fill in your password, check “remember password”, and choose a name you want to show up in the Jitsi UI. Hint: the display name handling sometimes seems buggy; restarting Jitsi sometimes helps.

  5. Now click “Next”, which takes you to the connection tab. Be sure to make all adjustments on this tab as shown below.
    Connection settings (click to enlarge)

    Connection settings (click to enlarge)

    The trick is to set “fritz.box” as the registrar (this is what your FritzBox uses for managing phone devices), and to set the public name of your FritzBox as the proxy (this is what your softphone uses to make the network connection). The port is 5060 for both. With this trick, you are using fritz.box as the domain for authentication on top of SIP, and the official hostname of the FritzBox for making the underlying Internet connection. Physically, both end up on the same device, so whichever handle your softphone uses, it all ends up in the right place.

  6. Click next to get to the security tab (shown below for completeness). Nothing to be changed here.

    Security settings (click to enlarge)

    Security settings (click to enlarge)

  7. Click next to move on to the presence tab. Set the two checkboxes as show below.

    Presence settings (click to enlarge)

    Presence settings (click to enlarge)

  8. Click next to get to the final encodings tab. Here it is important to check the “override global encoding settings”, and to make sure that only audio codecs labeled as “8000” are selected. Unselect all other audio codecs.
    Encoding settings (click to enlarge)

    Encoding settings (click to enlarge)

    The “8000” means 8000 audio samples per second. My FritzBox does not support any other sample rates, and this needs to be set manually. See my post  “Help! I sound like a robot!” for more information.

If you now click next once again, you will be presented with a summary of your settings. Hit “sign in” at the bottom, and you should be connected to the new phone device on your FritzBox. If you place a call from Jitsi, it will be coming from your regular phone landline. If you call your landline (e.g. from your cell phone), the analogue phone connected to your FritzBox will ring, and Jitsi will “ring” (i.e. indicate an incoming call). Click on the green handset to answer it on your laptop. Now, wherever in the world you are, when you have a network connection, you are able to place and take calls via your home phone. Magic!

There is one caveat, however: the transition to IPv6. My ISP is a progressive one, and gives me a native IPv6 connection. IPv4 is only provided via a DS-Lite tunnel for access to those websites that are still not reachable via IPv6 (but that’s a different debate). As a consequence, there is no A record for my box on MyFRITZ, but only an AAAA record. Practically it means that my FritzBox is only reachable via IPv6, but not via IPv4. When and where was the last public or hotel WiFi that gave you IPv6 service? There you go, I don’t remember either. If you want to be on the safe side, ask your ISP about the IPv4/v6 service they provide, and ask for “full dual stack” operation on your line. Happy SIP phoning!