.. _sec-ipv4:

IPv4 Configuration
~~~~~~~~~~~~~~~~~~

By default, NixOS uses DHCP (specifically, :command:`dhcpcd`) to
automatically configure network interfaces. However, you can configure an
interface manually as follows:

::

    `networking.interfaces.eth0.ipv4.addresses <None>`_  = [ {
      address = "192.168.1.2";
      prefixLength = 24;
    } ];

Typically you’ll also want to set a default gateway and set of name
servers:

.. parsed-literal::

    :ref:`opt-networking.defaultGateway`  = "192.168.1.1";
    :ref:`opt-networking.nameservers`  = [ "8.8.8.8" ];

.. note::

   Statically configured interfaces are set up by the systemd service
   *interface-name*``-cfg.service``.
   The default gateway and name server configuration is performed by
   ``network-setup.service``.

The host name is set using :ref:`opt-networking.hostName`:

.. parsed-literal::

    :ref:`opt-networking.hostName`  = "cartman";

The default host name is ``nixos``. Set it to the empty string
(``""``) to allow the DHCP server to provide the host name.