169 lines
4.3 KiB
XML
169 lines
4.3 KiB
XML
<chapter xmlns="http://docbook.org/ns/docbook"
|
||
xmlns:xlink="http://www.w3.org/1999/xlink"
|
||
xml:id="ch-configuration">
|
||
|
||
<title>Configuration</title>
|
||
|
||
<para>This chapter describes how to configure various aspects of a
|
||
NixOS machine through the configuration file
|
||
<filename>/etc/nixos/configuration.nix</filename>. As described in
|
||
<xref linkend="sec-changing-config" />, changes to that file only take
|
||
effect after you run <command>nixos-rebuild</command>.</para>
|
||
|
||
|
||
<!--===============================================================-->
|
||
|
||
<section><title>Networking</title>
|
||
|
||
<section><title>Secure shell access</title>
|
||
|
||
<para>Secure shell (SSH) access to your machine can be enabled by
|
||
setting:
|
||
|
||
<programlisting>
|
||
services.openssh.enable = true;
|
||
</programlisting>
|
||
|
||
By default, root logins using a password are disallowed. They can be
|
||
disabled entirely by setting
|
||
<literal>services.openssh.permitRootLogin</literal> to
|
||
<literal>"no"</literal>.</para>
|
||
|
||
<para>You can declaratively specify authorised RSA/DSA public keys for
|
||
a user as follows:
|
||
|
||
<!-- FIXME: this might not work if the user is unmanaged. -->
|
||
<programlisting>
|
||
users.extraUsers.alice.openssh.authorizedKeys.keys =
|
||
[ "ssh-dss AAAAB3NzaC1kc3MAAACBAPIkGWVEt4..." ];
|
||
</programlisting>
|
||
|
||
</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section><title>IPv4 configuration</title>
|
||
|
||
<para>By default, NixOS uses DHCP (specifically,
|
||
(<command>dhcpcd</command>)) to automatically configure network
|
||
interfaces. However, you can configure an interface manually as
|
||
follows:
|
||
|
||
<programlisting>
|
||
networking.interfaces.eth0 = { ipAddress = "192.168.1.2"; prefixLength = 24; };
|
||
</programlisting>
|
||
|
||
(The network prefix can also be specified using the option
|
||
<literal>subnetMask</literal>,
|
||
e.g. <literal>"255.255.255.0"</literal>, but this is deprecated.)
|
||
Typically you’ll also want to set a default gateway and set of name
|
||
servers:
|
||
|
||
<programlisting>
|
||
networking.defaultGateway = "192.168.1.1";
|
||
networking.nameservers = [ "8.8.8.8" ];
|
||
</programlisting>
|
||
|
||
</para>
|
||
|
||
<note><para>Statically configured interfaces are set up by the systemd
|
||
service
|
||
<replaceable>interface-name</replaceable><literal>-cfg.service</literal>.
|
||
The default gateway and name server configuration is performed by
|
||
<literal>network-setup.service</literal>.</para></note>
|
||
|
||
<para>The host name is set using <option>networking.hostName</option>:
|
||
|
||
<programlisting>
|
||
networking.hostName = "cartman";
|
||
</programlisting>
|
||
|
||
The default host name is <literal>nixos</literal>. Set it to the
|
||
empty string (<literal>""</literal>) to allow the DHCP server to
|
||
provide the host name.</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section><title>IPv6 configuration</title>
|
||
|
||
<para>IPv6 is enabled by default. Stateless address autoconfiguration
|
||
is used to automatically assign IPv6 addresses to all interfaces. You
|
||
can disable IPv6 support globally by setting:
|
||
|
||
<programlisting>
|
||
networking.enableIPv6 = false;
|
||
</programlisting>
|
||
|
||
</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section><title>Firewall</title>
|
||
|
||
<para>NixOS has a simple stateful firewall that blocks incoming
|
||
connections and other unexpected packets. The firewall applies to
|
||
both IPv4 and IPv6 traffic. It can be enabled as follows:
|
||
|
||
<programlisting>
|
||
networking.firewall.enable = true;
|
||
</programlisting>
|
||
|
||
You can open specific TCP ports to the outside world:
|
||
|
||
<programlisting>
|
||
networking.firewall.allowedTCPPorts = [ 80 443 ];
|
||
</programlisting>
|
||
|
||
Note that TCP port 22 (ssh) is opened automatically if the SSH daemon
|
||
is enabled (<option>services.openssh.enable = true</option>). UDP
|
||
ports can be opened through
|
||
<option>networking.firewall.allowedUDPPorts</option>. Also of
|
||
interest is
|
||
|
||
<programlisting>
|
||
networking.firewall.allowPing = true;
|
||
</programlisting>
|
||
|
||
to allow the machine to respond to ping requests. (ICMPv6 pings are
|
||
always allowed.)</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section><title>Wireless networks</title>
|
||
|
||
<para>TODO</para>
|
||
|
||
</section>
|
||
|
||
|
||
<section><title>Ad-hoc configuration</title>
|
||
|
||
<para>You can use <option>networking.localCommands</option> to specify
|
||
shell commands to be run at the end of
|
||
<literal>network-setup.service</literal>. This is useful for doing
|
||
network configuration not covered by the existing NixOS modules. For
|
||
instance, to statically configure an IPv6 address:
|
||
|
||
<programlisting>
|
||
networking.localCommands =
|
||
''
|
||
ip -6 addr add 2001:610:685:1::1/64 dev eth0
|
||
'';
|
||
</programlisting>
|
||
|
||
</para>
|
||
|
||
</section>
|
||
|
||
|
||
<!-- TODO: OpenVPN, NAT -->
|
||
|
||
|
||
</section>
|
||
|
||
|
||
</chapter>
|