FRITZ!Box 3390 Service - Knowledge Base
Access to the FRITZ!Box via Telnet is not supported
Telnet is an internal development interface and not a function of the FRITZ!Box. Starting with FRITZ!OS 6.25, Telnet is no longer supported and also cannot be installed accidentally. Enabling Telnet enabled an interface that could be used to make extensive and sometimes even harmful modifications to the FRITZ!Box. For this reason, we did not support FRITZ!Boxes with Telnet enabled. When it was activated, the message "changes not supported by manufacturer" was displayed on the "Overview" page of the FRITZ!Box user interface; this message could only be removed by running the recovery tool, which also deleted all of the FRITZ!Box settings.
AVM is open for FRITZ!Box users who actively participate in product development and also develop their own products (for example freetz). We also do not prevent users from installing custom-designed firmware if they really want to do so.