# IPv4 Configuration

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

    networking.interfaces.eth0.ipv4.addresses = [ {
      address = "192.168.1.2";
      prefixLength = 24;
    } ];

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

    networking.defaultGateway = "192.168.1.1";
    networking.nameservers = [ "8.8.8.8" ];

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 :

    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.