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<?xml version="1.0" encoding="UTF-8"?>
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<!DOCTYPE refentry PUBLIC "-//OASIS//DTD DocBook XML V4.5//EN"
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"http://www.oasis-open.org/docbook/xml/4.5/docbookx.dtd" [
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<!ENTITY VERSION "1.0">
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<!ENTITY COMMANDNAME "mandos">
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<!ENTITY TIMESTAMP "2022-04-24">
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<!ENTITY % common SYSTEM "common.ent">
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<!ENTITY OVERVIEW SYSTEM "overview.xml">
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<refentry xmlns:xi="http://www.w3.org/2001/XInclude">
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<title>Mandos Manual</title>
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<title>&COMMANDNAME;</title>
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<!-- NWalsh’s docbook scripts use this to generate the footer: -->
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<productname>Mandos</productname>
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<productnumber>&version;</productnumber>
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<date>&TIMESTAMP;</date>
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<productname>&COMMANDNAME;</productname>
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<productnumber>&VERSION;</productnumber>
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<firstname>Björn</firstname>
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<surname>Påhlsson</surname>
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<email>belorn@recompile.se</email>
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<email>belorn@fukt.bsnet.se</email>
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<firstname>Teddy</firstname>
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<surname>Hogeborn</surname>
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<email>teddy@recompile.se</email>
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<email>teddy@fukt.bsnet.se</email>
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<holder>Teddy Hogeborn</holder>
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<holder>Björn Påhlsson</holder>
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<xi:include href="legalnotice.xml"/>
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This manual page is free software: you can redistribute it
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and/or modify it under the terms of the GNU General Public
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License as published by the Free Software Foundation,
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either version 3 of the License, or (at your option) any
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This manual page is distributed in the hope that it will
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be useful, but WITHOUT ANY WARRANTY; without even the
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implied warranty of MERCHANTABILITY or FITNESS FOR A
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PARTICULAR PURPOSE. See the GNU General Public License
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You should have received a copy of the GNU General Public
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License along with this program; If not, see
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<ulink url="http://www.gnu.org/licenses/"/>.
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<refentrytitle>&COMMANDNAME;</refentrytitle>
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<manvolnum>8</manvolnum>
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<refname><command>&COMMANDNAME;</command></refname>
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Gives encrypted passwords to authenticated Mandos clients
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Sends encrypted passwords to authenticated Mandos clients
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<command>&COMMANDNAME;</command>
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<arg choice="plain"><option>--interface
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<replaceable>NAME</replaceable></option></arg>
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<arg choice="plain"><option>-i
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<replaceable>NAME</replaceable></option></arg>
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<arg choice="plain"><option>--address
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<replaceable>ADDRESS</replaceable></option></arg>
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<arg choice="plain"><option>-a
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<replaceable>ADDRESS</replaceable></option></arg>
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<arg choice="plain"><option>--port
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<replaceable>PORT</replaceable></option></arg>
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<arg choice="plain"><option>-p
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<replaceable>PORT</replaceable></option></arg>
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<arg><option>--priority
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<replaceable>PRIORITY</replaceable></option></arg>
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<arg><option>--servicename
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<replaceable>NAME</replaceable></option></arg>
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<arg><option>--configdir
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<replaceable>DIRECTORY</replaceable></option></arg>
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<arg><option>--debug</option></arg>
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<arg><option>--debuglevel
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<replaceable>LEVEL</replaceable></option></arg>
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<arg><option>--no-dbus</option></arg>
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<arg><option>--no-ipv6</option></arg>
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<arg><option>--no-restore</option></arg>
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<arg><option>--statedir
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<replaceable>DIRECTORY</replaceable></option></arg>
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<arg><option>--socket
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<replaceable>FD</replaceable></option></arg>
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<arg><option>--foreground</option></arg>
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<arg><option>--no-zeroconf</option></arg>
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<command>&COMMANDNAME;</command>
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<arg choice="plain"><option>--help</option></arg>
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<arg choice="plain"><option>-h</option></arg>
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<command>&COMMANDNAME;</command>
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<arg choice="plain"><option>--version</option></arg>
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<command>&COMMANDNAME;</command>
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<arg choice="plain"><option>--check</option></arg>
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<arg choice="opt">--interface<arg choice="plain">IF</arg></arg>
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<arg choice="opt">--address<arg choice="plain">ADDRESS</arg></arg>
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<arg choice="opt">--port<arg choice="plain">PORT</arg></arg>
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<arg choice="opt">--priority<arg choice="plain">PRIORITY</arg></arg>
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<arg choice="opt">--servicename<arg choice="plain">NAME</arg></arg>
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<arg choice="opt">--configdir<arg choice="plain">DIRECTORY</arg></arg>
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<arg choice="opt">--debug</arg>
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<command>&COMMANDNAME;</command>
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<arg choice="opt">-i<arg choice="plain">IF</arg></arg>
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<arg choice="opt">-a<arg choice="plain">ADDRESS</arg></arg>
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<arg choice="opt">-p<arg choice="plain">PORT</arg></arg>
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<arg choice="opt">--priority<arg choice="plain">PRIORITY</arg></arg>
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<arg choice="opt">--servicename<arg choice="plain">NAME</arg></arg>
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<arg choice="opt">--configdir<arg choice="plain">DIRECTORY</arg></arg>
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<arg choice="opt">--debug</arg>
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<command>&COMMANDNAME;</command>
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<arg choice="plain">--help</arg>
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<command>&COMMANDNAME;</command>
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<arg choice="plain">--version</arg>
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<command>&COMMANDNAME;</command>
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<arg choice="plain">--check</arg>
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</refsynopsisdiv>
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<refsect1 id="description">
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<title>DESCRIPTION</title>
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<command>&COMMANDNAME;</command> is a server daemon which
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handles incoming requests for passwords for a pre-defined list
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of client host computers. For an introduction, see
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<citerefentry><refentrytitle>intro</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
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uses Zeroconf to announce itself on the local network, and uses
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TLS to communicate securely with and to authenticate the
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clients. The Mandos server uses IPv6 to allow Mandos clients to
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use IPv6 link-local addresses, since the clients will probably
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not have any other addresses configured (see <xref
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linkend="overview"/>). Any authenticated client is then given
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the stored pre-encrypted password for that specific client.
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handles incoming request for passwords for a pre-defined list of
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client host computers. The Mandos server uses Zeroconf to
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announce itself on the local network, and uses TLS to
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communicate securely with and to authenticate the clients. The
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Mandos server uses IPv6 to allow Mandos clients to use IPv6
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link-local addresses, since the clients will probably not have
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any other addresses configured (see <xref linkend="overview"/>).
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Any authenticated client is then given the stored pre-encrypted
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password for that specific client.
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<refsect1 id="purpose">
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<title>PURPOSE</title>
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The purpose of this is to enable <emphasis>remote and unattended
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rebooting</emphasis> of client host computer with an
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<emphasis>encrypted root file system</emphasis>. See <xref
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linkend="overview"/> for details.
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<refsect1 id="options">
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<title>OPTIONS</title>
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<term><option>--help</option></term>
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<term><option>-h</option></term>
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<term><literal>-h</literal>, <literal>--help</literal></term>
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Show a help message and exit
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<term><option>--interface</option>
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<replaceable>NAME</replaceable></term>
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<term><option>-i</option>
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<replaceable>NAME</replaceable></term>
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<xi:include href="mandos-options.xml" xpointer="interface"/>
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<term><option>--address
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<replaceable>ADDRESS</replaceable></option></term>
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<replaceable>ADDRESS</replaceable></option></term>
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<xi:include href="mandos-options.xml" xpointer="address"/>
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<replaceable>PORT</replaceable></option></term>
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<replaceable>PORT</replaceable></option></term>
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<xi:include href="mandos-options.xml" xpointer="port"/>
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<term><option>--check</option></term>
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<term><literal>-i</literal>, <literal>--interface <replaceable>
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IF</replaceable></literal></term>
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Only announce the server and listen to requests on network
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interface <replaceable>IF</replaceable>. Default is to
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use all available interfaces.
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<term><literal>-a</literal>, <literal>--address <replaceable>
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ADDRESS</replaceable></literal></term>
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If this option is used, the server will only listen to a
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specific address. This must currently be an IPv6 address;
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an IPv4 address can be specified using the
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<quote><literal>::FFFF:192.0.2.3</literal></quote> syntax.
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Also, if a link-local address is specified, an interface
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should be set, since a link-local address is only valid on
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a single interface. By default, the server will listen to
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all available addresses.
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<term><literal>-p</literal>, <literal>--port <replaceable>
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PORT</replaceable></literal></term>
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If this option is used, the server to bind to that
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port. By default, the server will listen to an arbitrary
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port given by the operating system.
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<term><literal>--check</literal></term>
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Run the server’s self-tests. This includes any unit
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<term><option>--debug</option></term>
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<xi:include href="mandos-options.xml" xpointer="debug"/>
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<term><option>--debuglevel
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<replaceable>LEVEL</replaceable></option></term>
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Set the debugging log level.
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<replaceable>LEVEL</replaceable> is a string, one of
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<quote><literal>CRITICAL</literal></quote>,
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<quote><literal>ERROR</literal></quote>,
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<quote><literal>WARNING</literal></quote>,
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<quote><literal>INFO</literal></quote>, or
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<quote><literal>DEBUG</literal></quote>, in order of
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increasing verbosity. The default level is
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<quote><literal>WARNING</literal></quote>.
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<term><option>--priority <replaceable>
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PRIORITY</replaceable></option></term>
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<xi:include href="mandos-options.xml" xpointer="priority"/>
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<term><option>--servicename
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<replaceable>NAME</replaceable></option></term>
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<xi:include href="mandos-options.xml"
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xpointer="servicename"/>
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<term><option>--configdir
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<replaceable>DIRECTORY</replaceable></option></term>
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<term><literal>--debug</literal></term>
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If the server is run in debug mode, it will run in the
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foreground and print a lot of debugging information. The
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default is <emphasis>not</emphasis> to run in debug mode.
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<term><literal>--priority <replaceable>
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PRIORITY</replaceable></literal></term>
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GnuTLS priority string for the TLS handshake with the
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clients. The default is
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<quote><literal>SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP</literal></quote>.
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See <citerefentry><refentrytitle>gnutls_priority_init
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</refentrytitle><manvolnum>3</manvolnum></citerefentry>
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for the syntax. <emphasis>Warning</emphasis>: changing
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this may make the TLS handshake fail, making communication
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with clients impossible.
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<term><literal>--servicename <replaceable>NAME</replaceable>
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Zeroconf service name. The default is
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<quote><literal>Mandos</literal></quote>. You only need
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to change this if you for some reason want to run more
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than one server on the same <emphasis>host</emphasis>,
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which would not normally be useful. If there are name
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collisions on the same <emphasis>network</emphasis>, the
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newer server will automatically rename itself to
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<quote><literal>Mandos #2</literal></quote>, and so on;
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therefore, this option is not needed in that case.
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<term><literal>--configdir <replaceable>DIR</replaceable>
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Directory to search for configuration files. Default is
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<term><option>--version</option></term>
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<term><literal>--version</literal></term>
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Prints the program version and exit.
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<term><option>--no-dbus</option></term>
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<xi:include href="mandos-options.xml" xpointer="dbus"/>
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See also <xref linkend="dbus_interface"/>.
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<term><option>--no-ipv6</option></term>
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<xi:include href="mandos-options.xml" xpointer="ipv6"/>
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<term><option>--no-restore</option></term>
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<xi:include href="mandos-options.xml" xpointer="restore"/>
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See also <xref linkend="persistent_state"/>.
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<term><option>--statedir
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<replaceable>DIRECTORY</replaceable></option></term>
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<xi:include href="mandos-options.xml" xpointer="statedir"/>
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<term><option>--socket
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<replaceable>FD</replaceable></option></term>
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<xi:include href="mandos-options.xml" xpointer="socket"/>
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<term><option>--foreground</option></term>
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<xi:include href="mandos-options.xml"
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xpointer="foreground"/>
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<term><option>--no-zeroconf</option></term>
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<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
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<refsect1 id="overview">
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<title>OVERVIEW</title>
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<xi:include href="overview.xml"/>
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This program is the server part. It is a normal server program
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and will run in a normal system environment, not in an initial
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<acronym>RAM</acronym> disk environment.
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RAM disk environment.
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<refsect1 id="protocol">
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<title>NETWORK PROTOCOL</title>
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</tbody></tgroup></table>
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<refsect1 id="checking">
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<title>CHECKING</title>
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The server will, by default, continually check that the clients
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are still up. If a client has not been confirmed as being up
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for some time, the client is assumed to be compromised and is no
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longer eligible to receive the encrypted password. (Manual
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intervention is required to re-enable a client.) The timeout,
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extended timeout, checker program, and interval between checks
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can be configured both globally and per client; see
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<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
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longer eligible to receive the encrypted password. The timeout,
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checker program, and interval between checks can be configured
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both globally and per client; see <citerefentry>
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<refentrytitle>mandos.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
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<refentrytitle>mandos-clients.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry>.
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<refsect1 id="approval">
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<title>APPROVAL</title>
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The server can be configured to require manual approval for a
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client before it is sent its secret. The delay to wait for such
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approval and the default action (approve or deny) can be
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configured both globally and per client; see <citerefentry>
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<refentrytitle>mandos-clients.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry>. By default all clients
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will be approved immediately without delay.
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This can be used to deny a client its secret if not manually
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approved within a specified time. It can also be used to make
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the server delay before giving a client its secret, allowing
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optional manual denying of this specific client.
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<refsect1 id="logging">
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<title>LOGGING</title>
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The server will send log message with various severity levels to
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<filename class="devicefile">/dev/log</filename>. With the
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The server will send log messaged with various severity levels
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to <filename>/dev/log</filename>. With the
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<option>--debug</option> option, it will log even more messages,
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and also show them on the console.
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<refsect1 id="persistent_state">
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<title>PERSISTENT STATE</title>
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Client settings, initially read from
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<filename>clients.conf</filename>, are persistent across
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restarts, and run-time changes will override settings in
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<filename>clients.conf</filename>. However, if a setting is
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<emphasis>changed</emphasis> (or a client added, or removed) in
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<filename>clients.conf</filename>, this will take precedence.
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<refsect1 id="dbus_interface">
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<title>D-BUS INTERFACE</title>
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The server will by default provide a D-Bus system bus interface.
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This interface will only be accessible by the root user or a
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Mandos-specific user, if such a user exists. For documentation
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of the D-Bus API, see the file <filename>DBUS-API</filename>.
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<refsect1 id="exit_status">
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<title>EXIT STATUS</title>
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<term><filename>/bin/sh</filename></term>
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This is used to start the configured checker command for
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each client. See <citerefentry>
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<refentrytitle>mandos-clients.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry> for details.
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<refsect1 id="bugs">
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<title>BUGS</title>
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This server might, on especially fatal errors, emit a Python
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backtrace. This could be considered a feature.
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There is no fine-grained control over logging and debug output.
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<xi:include href="bugs.xml"/>
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<refsect1 id="example">
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<title>EXAMPLE</title>
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<refsect1 id="examples">
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<title>EXAMPLES</title>
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<informalexample>
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Normal invocation needs no options:
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<userinput>&COMMANDNAME;</userinput>
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<userinput>mandos</userinput>
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</informalexample>
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<informalexample>
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Run the server in debug mode, read configuration files from
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the <filename class="directory">~/mandos</filename> directory,
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and use the Zeroconf service name <quote>Test</quote> to not
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collide with any other official Mandos server on this host:
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the <filename>~/mandos</filename> directory, and use the
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Zeroconf service name <quote>Test</quote> to not collide with
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any other official Mandos server on this host:
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<!-- do not wrap this line -->
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<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
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<userinput>mandos --debug --configdir ~/mandos --servicename Test</userinput>
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</informalexample>
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<!-- do not wrap this line -->
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<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
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<userinput>mandos --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
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</informalexample>
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<refsect1 id="security">
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<title>SECURITY</title>
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<refsect2 id="server">
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<title>SERVER</title>
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Running this <command>&COMMANDNAME;</command> server program
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should not in itself present any security risk to the host
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computer running it. The program switches to a non-root user
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Running this &COMMANDNAME; server program should not in itself
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present any security risk to the host computer running it.
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The program does not need any special privileges to run, and
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is designed to run as a non-root user.
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<refsect2 id="clients">
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<title>CLIENTS</title>
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The server only gives out its stored data to clients which
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does have the correct key ID of the stored key ID. This is
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guaranteed by the fact that the client sends its public key in
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the TLS handshake; this ensures it to be genuine. The server
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computes the key ID of the key itself and looks up the key ID
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in its list of clients. The <filename>clients.conf</filename>
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does have the OpenPGP key of the stored fingerprint. This is
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guaranteed by the fact that the client sends its OpenPGP
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public key in the TLS handshake; this ensures it to be
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genuine. The server computes the fingerprint of the key
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itself and looks up the fingerprint in its list of
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clients. The <filename>clients.conf</filename> file (see
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<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry>)
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<emphasis>must</emphasis> be made non-readable by anyone
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except the user starting the server (usually root).
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except the user running the server.
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As detailed in <xref linkend="checking"/>, the status of all
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For more details on client-side security, see
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<citerefentry><refentrytitle>mandos-client</refentrytitle>
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<citerefentry><refentrytitle>password-request</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>.
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<refsect1 id="see_also">
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<title>SEE ALSO</title>
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<citerefentry><refentrytitle>intro</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>mandos.conf</refentrytitle>
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<manvolnum>5</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>mandos-client</refentrytitle>
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<manvolnum>8mandos</manvolnum></citerefentry>,
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<citerefentry><refentrytitle>sh</refentrytitle>
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<manvolnum>1</manvolnum></citerefentry>
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<refentrytitle>password-request</refentrytitle>
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<manvolnum>8mandos</manvolnum>
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This is the actual program which talks to this server.
522
Note that it is normally not invoked directly, and is only
523
run in the initial RAM disk environment, and not on a
524
fully started system.
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<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
709
<ulink url="https://gnutls.org/">GnuTLS</ulink>
553
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
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GnuTLS is the library this server uses to implement TLS for
714
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communicating securely with the client, and at the same time
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confidently get the client’s public key.
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confidently get the client’s public OpenPGP key.
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RFC 4291: <citetitle>IP Version 6 Addressing
722
Architecture</citetitle>
565
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
566
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
567
Unicast Addresses</citation>
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<term>Section 2.2: <citetitle>Text Representation of
728
Addresses</citetitle></term>
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<listitem><para/></listitem>
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<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
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Address</citetitle></term>
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<listitem><para/></listitem>
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<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
738
Addresses</citetitle></term>
741
The clients use IPv6 link-local addresses, which are
742
immediately usable since a link-local address is
743
automatically assigned to a network interfaces when it
571
The clients use IPv6 link-local addresses, which are
572
immediately usable since a link-local addresses is
573
automatically assigned to a network interfaces when it is
753
RFC 5246: <citetitle>The Transport Layer Security (TLS)
754
Protocol Version 1.2</citetitle>
580
<citation>RFC 4346: <citetitle>The Transport Layer Security
581
(TLS) Protocol Version 1.1</citetitle></citation>
758
TLS 1.2 is the protocol implemented by GnuTLS.
585
TLS 1.1 is the protocol implemented by GnuTLS.
764
RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
591
<citation>RFC 4880: <citetitle>OpenPGP Message
592
Format</citetitle></citation>