.. _param-mmanon-ipv4-mode:
.. _mmanon.parameter.input.ipv4-mode:

ipv4.mode
=========

.. index::
   single: mmanon; ipv4.mode
   single: ipv4.mode

.. summary-start

Selects the IPv4 anonymization mode used by the mmanon action.

.. summary-end

This parameter applies to :doc:`../../configuration/modules/mmanon`.

:Name: ipv4.mode
:Scope: input
:Type: string
:Default: input=zero
:Required?: no
:Introduced: 7.3.7

Description
-----------
The available modes are ``simple``, ``random``, ``random-consistent``, and
``zero``.
In simple mode, only octets as a whole can be anonymized and the length of the
message is never changed. This means that when the last three octets of the
address 10.1.12.123 are anonymized, the result will be 10.x.xx.xxx.
The replacement character is configurable via
:ref:`ipv4.replaceChar <param-mmanon-ipv4-replacechar>`.
This means that the length of the original octets is still visible and may
be used to draw some privacy-evasive conclusions. This mode is slightly
faster than the other modes, and this may matter in high throughput
environments.

The modes ``random`` and ``random-consistent`` are very similar, in that
they both anonymize IP addresses by randomizing the last bits (any number)
of a given address. However, while ``random`` mode assigns a new random IP
address for every address in a message, ``random-consistent`` will assign
the same randomized address to every instance of the same original address.

The default ``zero`` mode will do full anonymization of any number of bits.
It will also normalize the address, so that no information about the original
IP address is available. For example, if 24 bits are anonymized, 10.1.12.123
would be anonymized to 10.0.0.0.

Input usage
-----------
.. _mmanon.parameter.input.ipv4-mode-usage:

.. code-block:: rsyslog

   module(load="mmanon")
   action(type="mmanon" ipv4.mode="random-consistent")

Legacy names (for reference)
~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Historic names/directives for compatibility. Do not use in new configs.

.. _mmanon.parameter.legacy.mode:

- mode — maps to ipv4.mode (status: legacy)

.. index::
   single: mmanon; mode
   single: mode

See also
--------
:doc:`../../configuration/modules/mmanon`