38 lines
1.1 KiB
XML
38 lines
1.1 KiB
XML
<section xmlns="http://docbook.org/ns/docbook"
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xmlns:xlink="http://www.w3.org/1999/xlink"
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xmlns:xi="http://www.w3.org/2001/XInclude"
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version="5.0"
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xml:id="sec-firewall">
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<title>Firewall</title>
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<para>NixOS has a simple stateful firewall that blocks incoming
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connections and other unexpected packets. The firewall applies to
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both IPv4 and IPv6 traffic. It is enabled by default. It can be
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disabled as follows:
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<programlisting>
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networking.firewall.enable = false;
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</programlisting>
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If the firewall is enabled, you can open specific TCP ports to the
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outside world:
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<programlisting>
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networking.firewall.allowedTCPPorts = [ 80 443 ];
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</programlisting>
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Note that TCP port 22 (ssh) is opened automatically if the SSH daemon
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is enabled (<option>services.openssh.enable = true</option>). UDP
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ports can be opened through
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<option>networking.firewall.allowedUDPPorts</option>. Also of
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interest is
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<programlisting>
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networking.firewall.allowPing = true;
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</programlisting>
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to allow the machine to respond to ping requests. (ICMPv6 pings are
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always allowed.)</para>
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</section>
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