Posts tagged fritzbox

fritzbox: factory reset

posted on 2015-12-07 06:01:23

Factory resetting a fritzbox can either be done via the menu, if you can still log in. But in case you forgot your password and have to reset it, you have to use your phone:


If they had built a proper reset button into the box, it'd been way better. If I do not err somehow, theoretically you can practically brick your device with no chance of resetting it when you do not have phone configured.

In case you have a phone and it still does not work, consult the official documentation on potential corner cases.

fritzbox: find out cpu architecture

posted on 2015-02-23 01:16:59

To find out which architecture your fritzbox' cpu has, try this:

if egrep -q 'AR9|AR10|VR9|Fusiv' /proc/cpuinfo; then echo "CPU: mips"; else echo "CPU: mipsel"; fi

Older ones are mipsel, whereas newer ones are of mips architecture.

fritzbox: install ssh server

posted on 2015-02-22 17:38:27

After having enabled the telnet access to your fritz box, which involves a phone connected to the device and dialing a number as described here, connect to its ip:

connect via telnet

[jl@jerrylee ~]% telnet                                               
Connected to
Escape character is '^]'.

BusyBox v1.20.2 (2014-09-26 13:25:19 CEST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

ermittle die aktuelle TTY
tty is "/dev/pts/0"
Console Ausgaben auf dieses Terminal umgelenkt
disable start/stop characters and flowcontrol

check architecture

Depending on the architecuture of the fritzbox cpu, you need a different binary. Older fritzboxes had mipsel cpu's whereas newer ones have mips ones. You may find this here helpful. Later this check is integrated into the install script, so no real need to bother with it now.

install overview

Several steps are needed, to achieve what is desired: (is automated in next section)

  1. set a root password

  2. copy the hashed password

  3. check cpu architecture

  4. install appropriate dropbear ssh server, depending on the platform


actual installation

From there on, do these steps: (tried to make these foolproof by using absolute paths)

cd /var
chmod 755 /var/cfg_dropbear

In case you wondered what this 'spblinux' distro is, this is what the sourceforge page tells:

    modular mini distribution running completely in RAM
    can be booted from USB
    based on Busybox and Midnight Commander
    optional with DirectFB and (since version 2.1) Mozilla
    it is possible to create/modify own modules inside SPB:Linux.

Enable fritzbox telnet access

posted on 2015-01-15 23:55:52

To enable the telnet access on a, try using a connected phone and dial:


To disable it again dial:


Once the phone dialled the number, just hang up after you heard the single beep. Maybe the presence of the beep depends on the type of phone used, I do not know.

First trying telnet access gives you this:

[jl@jerrylee ~]% telnet                                               
telnet: connect to address Connection refused
[jl@jerrylee ~]%


[jl@jerrylee ~]% telnet                                               
Connected to
Escape character is '^]'.

BusyBox v1.19.3 (2012-08-07 18:33:02 CEST) built-in shell (ash)
Enter 'help' for a list of built-in commands.

ermittle die aktuelle TTY
tty is "/dev/pts/0"
Console Ausgaben auf dieses Terminal umgelenkt

The password you are asked for, is the one you set up for the gui login.

This blog covers .csv, .htaccess, .pfx, .vmx, /etc/crypttab, /etc/network/interfaces, /etc/sudoers, /proc, 10.04, 14.04, AS, ASA, ControlPanel, DS1054Z, GPT, HWR, Hyper-V, IPSEC, KVM, LSI, LVM, LXC, MBR, MTU, MegaCli, PHP, PKI, R, RAID, S.M.A.R.T., SNMP, SSD, SSL, TLS, TRIM, VEEAM, VMware, VServer, VirtualBox, Virtuozzo, XenServer, acpi, adaptec, algorithm, ansible, apache, apache2.4, apachebench, apple, applet, arcconf, arch, architecture, areca, arping, asa, asdm, autoconf, awk, backup, bandit, bar, bash, benchmarking, binding, bitrate, blackarmor, blockdev, blowfish, bochs, bond, bonding, booknotes, bootable, bsd, btrfs, buffer, c-states, cache, caching, ccl, centos, certificate, certtool, cgdisk, cheatsheet, chrome, chroot, cisco, clamav, cli, clp, clush, cluster, coleslaw, colorscheme, common lisp, configuration management, console, container, containers, controller, cron, cryptsetup, csync2, cu, cups, cygwin, d-states, database, date, db2, dcfldd, dcim, dd, debian, debug, debugger, debugging, decimal, desktop, df, dhclient, dhcp, diff, dig, display manager, dm-crypt, dmesg, dmidecode, dns, docker, dos, drivers, dtrace, dtrace4linux, du, dynamictracing, e2fsck, eBPF, ebook, efi, egrep, emacs, encoding, env, error, ess, esx, esxcli, esxi, ethtool, evil, expect, exportfs, factory reset, factory_reset, factoryreset, fail2ban, fbsd, fdisk, fedora, file, filesystem, find, fio, firewall, firmware, fish, flashrom, forensics, free, freebsd, freedos, fritzbox, fsck, fstrim, ftp, ftps, g-states, gentoo, ghostscript, git, git-filter-branch, github, gitolite, global, gnutls, gradle, grep, grml, grub, grub2, guacamole, hardware, haskell, hdd, hdparm, hellowor, hex, hexdump, history, howto, htop, htpasswd, http, httpd, https, i3, icmp, ifenslave, iftop, iis, imagemagick, imap, imaps, init, innoDB, innodb, inodes, intel, ioncube, ios, iostat, ip, iperf, iphone, ipmi, ipmitool, iproute2, ipsec, iptables, ipv6, irc, irssi, iw, iwconfig, iwlist, iwlwifi, jailbreak, jails, java, javascript, javaws, js, juniper, junit, kali, kde, kemp, kernel, keyremap, kill, kpartx, krypton, lacp, lamp, languages, ldap, ldapsearch, less, leviathan, liero, lightning, links, linux, linuxin3months, lisp, list, livedisk, lmctfy, loadbalancing, locale, log, logrotate, looback, loopback, losetup, lsblk, lsi, lsof, lsusb, lsyncd, luks, lvextend, lvm, lvm2, lvreduce, lxc, lxde, macbook, macro, magento, mailclient, mailing, mailq, manpages, markdown, mbr, mdadm, megacli, micro sd, microsoft, minicom, mkfs, mktemp, mod_pagespeed, mod_proxy, modbus, modprobe, mount, mouse, movement, mpstat, multitasking, myISAM, mysql, mysql 5.7, mysql workbench, mysqlcheck, mysqldump, nagios, nas, nat, nc, netfilter, networking, nfs, nginx, nmap, nocaps, nodejs, numberingsystem, numbers, od, onyx, opcode-cache, openVZ, openlierox, openssl, openvpn, openvswitch, openwrt, oracle linux, org-mode, os, oscilloscope, overview, parallel, parameter expansion, parted, partitioning, passwd, patch, pct, pdf, performance, pfsense, php, php7, phpmyadmin, pi, pidgin, pidstat, pins, pkill, plasma, plesk, plugin, posix, postfix, postfixadmin, postgres, postgresql, poudriere, powershell, preview, profiling, prompt, proxmox, ps, puppet, pv, pveam, pvecm, pvesm, pvresize, python, qemu, qemu-img, qm, qmrestore, quicklisp, quickshare, r, racktables, raid, raspberry pi, raspberrypi, raspbian, rbpi, rdp, redhat, redirect, registry, requirements, resize2fs, rewrite, rewrites, rhel, rigol, roccat, routing, rs0485, rs232, rsync, s-states, s_client, samba, sar, sata, sbcl, scite, scp, screen, scripting, seafile, seagate, security, sed, serial, serial port, setup, sftp, sg300, shell, shopware, shortcuts, showmount, signals, slattach, slip, slow-query-log, smbclient, snmpget, snmpwalk, software RAID, software raid, softwareraid, sophos, spacemacs, spam, specification, speedport, spi, sqlite, squid, ssd, ssh, ssh-add, sshd, ssl, stats, storage, strace, stronswan, su, submodules, subzone, sudo, sudoers, sup, swaks, swap, switch, switching, synaptics, synergy, sysfs, systemd, systemtap, tar, tcpdump, tcsh, tee, telnet, terminal, terminator, testdisk, testing, throughput, tmux, todo, tomcat, top, tput, trafficshaping, ttl, tuning, tunnel, tunneling, typo3, uboot, ubuntu, ubuntu 16.04, udev, uefi, ulimit, uname, unetbootin, unit testing, upstart, uptime, usb, usbstick, utf8, utm, utm 220, ux305, vcs, vgchange, vim, vimdiff, virtualbox, virtualization, visual studio code, vlan, vmstat, vmware, vnc, vncviewer, voltage, vpn, vsphere, vzdump, w, w701, wakeonlan, wargames, web, webdav, weechat, wget, whois, wicd, wifi, windowmanager, windows, wine, wireshark, wpa, wpa_passphrase, wpa_supplicant, x11vnc, x2x, xfce, xfreerdp, xmodem, xterm, xxd, yum, zones, zsh

Unless otherwise credited all material Creative Commons License by sjas