FRITZ!Box 5491 Service - Knowledge Base

FRITZ!Box 5491 Service

Configuring FRITZ!Box to always assign the same IP address to a network device

The FRITZ!Box's DHCP (Dynamic Host Configuration Protocol) server automatically assigns each computer, smartphone, and other network device all of the IP settings required to communicate with the internet and other devices in the home network.

By default, the FRITZ!Box always assigns the same IP address to each device. For this, the FRITZ!Box permanently stores the device's MAC address with the first IP address assigned to it.

The FRITZ!Box only assigns a new IP address to a device if the maximum number of IP addresses in the IP network being used has been reached. However, you can also configure the FRITZ!Box so that it always assigns the same IP address to a device, for example if you want to configure port sharing for the device.

Requirements / Restrictions

Note:All instructions on configuration and settings given in this guide refer to the latest FRITZ!OS for the FRITZ!Box.

1 Enabling the FRITZ!Box's DHCP server

In the factory settings, the FRITZ!Box automatically assigns the correct IP settings to all devices via DHCP. If you disabled the FRITZ!Box's DHCP server, re-enable it:

  1. Click "Home Network" in the FRITZ!Box user interface.
  2. Click "Network" in the "Home Network" menu.
  3. Click on the "Network Settings" tab.
  4. Click the "IPv4 Addresses" button. If the button is not displayed, enable the Advanced View first.
  5. Enable the DHCP server and define the range from which the FRITZ!Box assigns IP addresses.

    Note:The FRITZ!Box has the IP address (subnet mask and assigns IP addresses from xxx.20 to xxx.200 in the factory settings.

  6. Click "OK" to save the settings.

2 Configuring assignment of fixed IP addresses for network device

  1. Click "Home Network" in the FRITZ!Box user interface.
  2. Click "Network" in the "Home Network" menu.
  3. Click on the "Network Connections" tab.
  4. Click the (Edit) button for the device you want to configure.
  5. Enable the option "Always assign this network device the same IPv4 address".
  6. If the device should be assigned a specific IP address, enter the desired IP address in the "IPv4 address" field.

    Important:The IP address may not already be used by any other device and it must be from the FRITZ!Box's IP network ( The IP address may be within or outside the DHCP range (factory setting: 20 to 200).

  7. Click "OK" to save the settings.