Right now I am in the process of migrating everything except telephony off my FRITZ!Box. After a lot of experimentation, sleepless nights and much frustration, I have come to the following conclusions about FRITZ!’s little all-in-one device.
Running the FRITZ!Box in IP-Client mode is basically impossible due to the sheer number of bugs. In this mode the router becomes just another client device in the network.
In theory this should be exactly what I want. It receives it’s IP address via DHCP and only acts as a SIP gateway. Or so you think. Because it doesn’t do jack shit. Once in IP-Client mode, the box no longer cares about WAN IP changes. It doesn’t even detect pulling all ethernet cables and just goes on being “online”.
Because of this, WAN IP changes do not cause a SIP REGISTER packet to be sent, meaning that you will have to wait the allotted time defined as REGISTER renewal in the original REGISTER response. In the meantime you cannot accept or initiate calls. Good stuff, FRITZ!
Now in the olden times people were able to activate telnet access to their FRITZ!Box and put a simple shell script into the debug.cfg to check for WAN IP changes and to reload the voipd if necessary.
But no worries, this feature has long been deactivated, so that absolutely no means of fixing a 15 year old issue are present anymore. Yes, you can restart the device through TR-064 via a shell script from another system, however I am not a fan of restarting an entire device because one teeny tiny option is missing. So… Good stuff, FRITZ!
And just to be extra annoying the FRITZ!Box decided to enable PVC on its own. Even finding the source of this issue took a good amount of time because why would I ever look at settings that I never changed to begin with? Good stuff, FRITZ!
While we are on the topic of settings: You cannot change the local domain name from fritz.box to something compliant with a .internal domain. Good stuff, FRITZ!, please ensure your fancy domain name keeps getting renewed.
All of these issues point to poor software quality or malicious compliance. Even without the ability to access the internals of the device and just by using the web interface (after several factory resets, to boot!) I was able to produce a ton of bugs and seemingly configuration corruptions when using the device in IP-Client mode.
Why telephony in IP-Client mode doesn’t regularly poll its own WAN IP to re-issue a REGISTER on change is beyond me. Why upstream gateways are not being accepted unless a static IP address is provided is also beyond me. Why this device is the only device on my entire network to behave so catastrophically uncompliant? I wish I knew.
There is no doubt that for regular households a FRITZ!Box is an excellent device. TR-069 automatically pulls the configuration for subscribers, WiFi configuration is dead simple, telephony has all the basic features you need. And all of that is pretty much working great when in router mode. But as soon as you switch into IP-Client mode, even after a full factory reset, the device breaks apart.
Skimming over 10-15 years worth of forum posts in search of solutions to seemingly wide-spread problems leaves me with the following conclusion: Instead of addressing long-standing problems within the networking core of the product, FRITZ! seemingly focuses on FRITZ!nas (because everyone and their dog uses their underpowered router as a NAS), on increasing the filter lists from 10 to 12 or on releasing another model of a FRITZ!Box with 1G ports.
The final verdict is that I will have to use the FRITZ!Box as a modem/router combo just so that I can keep the telephony features working reliably. Unfortunately it needs to sit at the front door because it cannot comprehend what a window is. Because unless it runs as a router, a lot of features of the FRITZ!Box simply stop working reliably or actively break.
Everything (including WiFi) apart from telephony will move behind the UniFi Gateway Fiber, using dedicated hardware.
What a shame, FRITZ! always stood for “not fancy, but reliable and compliant”. I’ve been using their hardware since the late 1990s, starting with the FRITZ! PCI ISDN card. Lately, their hardware offerings have been rather weak (why doesn’t the FRITZ!Box 5690 Pro have 10Gbit WAN ports? Why is there no XGPON/XGSPON support present?) and the reliability of the routers have been middling.
My 5690 Pro keeps crashing (as in: the device has to reboot) when certain WiFi settings are active. Extremely “Pro”. Makes you wonder if it will end up like a 7590 with hardware defects after 5 years due to maliciously misused components. Because we all love planned obsolescence!
While I do have my gripes with UniFi as well, it is at least “the Apple of networking stuff”: Nice user experience for dummies like me who want more control but are not Cisco-certified network gods. And I can change the gosh darn DHCP parameters like network boot and TFTP! Imagine that! And thanks to the SFP+ slot on the Gateway Fiber and a nifty X-GPON SFP module, I can quickly (!) bring up a backup GPON connection should the FRITZ!Box ever shit the bed, since all of the network topology is already behind (or will soon be behind) the gateway. Imagine that!
