68
57
<refname><command>&COMMANDNAME;</command></refname>
70
Sends encrypted passwords to authenticated Mandos clients
59
Gives encrypted passwords to authenticated Mandos clients
76
65
<command>&COMMANDNAME;</command>
77
<arg choice='opt'>--interface<arg choice='plain'>IF</arg></arg>
78
<arg choice='opt'>--address<arg choice='plain'>ADDRESS</arg></arg>
79
<arg choice='opt'>--port<arg choice='plain'>PORT</arg></arg>
80
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
81
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
82
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
83
<arg choice='opt'>--debug</arg>
86
<command>&COMMANDNAME;</command>
87
<arg choice='opt'>-i<arg choice='plain'>IF</arg></arg>
88
<arg choice='opt'>-a<arg choice='plain'>ADDRESS</arg></arg>
89
<arg choice='opt'>-p<arg choice='plain'>PORT</arg></arg>
90
<arg choice='opt'>--priority<arg choice='plain'>PRIORITY</arg></arg>
91
<arg choice='opt'>--servicename<arg choice='plain'>NAME</arg></arg>
92
<arg choice='opt'>--configdir<arg choice='plain'>DIRECTORY</arg></arg>
93
<arg choice='opt'>--debug</arg>
96
<command>&COMMANDNAME;</command>
97
<arg choice='plain'>--help</arg>
100
<command>&COMMANDNAME;</command>
101
<arg choice='plain'>--version</arg>
104
<command>&COMMANDNAME;</command>
105
<arg choice='plain'>--check</arg>
67
<arg choice="plain"><option>--interface
68
<replaceable>NAME</replaceable></option></arg>
69
<arg choice="plain"><option>-i
70
<replaceable>NAME</replaceable></option></arg>
74
<arg choice="plain"><option>--address
75
<replaceable>ADDRESS</replaceable></option></arg>
76
<arg choice="plain"><option>-a
77
<replaceable>ADDRESS</replaceable></option></arg>
81
<arg choice="plain"><option>--port
82
<replaceable>PORT</replaceable></option></arg>
83
<arg choice="plain"><option>-p
84
<replaceable>PORT</replaceable></option></arg>
87
<arg><option>--priority
88
<replaceable>PRIORITY</replaceable></option></arg>
90
<arg><option>--servicename
91
<replaceable>NAME</replaceable></option></arg>
93
<arg><option>--configdir
94
<replaceable>DIRECTORY</replaceable></option></arg>
96
<arg><option>--debug</option></arg>
98
<arg><option>--debuglevel
99
<replaceable>LEVEL</replaceable></option></arg>
101
<arg><option>--no-dbus</option></arg>
103
<arg><option>--no-ipv6</option></arg>
105
<arg><option>--no-restore</option></arg>
107
<arg><option>--statedir
108
<replaceable>DIRECTORY</replaceable></option></arg>
110
<arg><option>--socket
111
<replaceable>FD</replaceable></option></arg>
113
<arg><option>--foreground</option></arg>
115
<arg><option>--no-zeroconf</option></arg>
118
<command>&COMMANDNAME;</command>
120
<arg choice="plain"><option>--help</option></arg>
121
<arg choice="plain"><option>-h</option></arg>
125
<command>&COMMANDNAME;</command>
126
<arg choice="plain"><option>--version</option></arg>
129
<command>&COMMANDNAME;</command>
130
<arg choice="plain"><option>--check</option></arg>
107
132
</refsynopsisdiv>
109
134
<refsect1 id="description">
110
135
<title>DESCRIPTION</title>
112
137
<command>&COMMANDNAME;</command> is a server daemon which
113
138
handles incoming request for passwords for a pre-defined list of
114
client host computers. The Mandos server uses Zeroconf to
115
announce itself on the local network, and uses GnuTLS to
116
communicate securely with and to authenticate the clients.
117
Mandos uses IPv6 link-local addresses, since the clients are
118
assumed to not have any other addresses configured yet. Any
119
authenticated client is then given the pre-encrypted password
120
for that specific client.
139
client host computers. For an introduction, see
140
<citerefentry><refentrytitle>intro</refentrytitle>
141
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
142
uses Zeroconf to announce itself on the local network, and uses
143
TLS to communicate securely with and to authenticate the
144
clients. The Mandos server uses IPv6 to allow Mandos clients to
145
use IPv6 link-local addresses, since the clients will probably
146
not have any other addresses configured (see <xref
147
linkend="overview"/>). Any authenticated client is then given
148
the stored pre-encrypted password for that specific client.
125
152
<refsect1 id="purpose">
126
153
<title>PURPOSE</title>
129
155
The purpose of this is to enable <emphasis>remote and unattended
130
rebooting</emphasis> of any client host computer with an
131
<emphasis>encrypted root file system</emphasis>. The client
132
host computer should start a Mandos client in the initial RAM
133
disk environment, the Mandos client program communicates with
134
this server program to get an encrypted password, which is then
135
decrypted and used to unlock the encrypted root file system.
136
The client host computer can then continue its boot sequence
156
rebooting</emphasis> of client host computer with an
157
<emphasis>encrypted root file system</emphasis>. See <xref
158
linkend="overview"/> for details.
142
162
<refsect1 id="options">
143
163
<title>OPTIONS</title>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
166
<term><option>--help</option></term>
167
<term><option>-h</option></term>
150
170
Show a help message and exit
156
<term><literal>-i</literal>, <literal>--interface <replaceable>
157
IF</replaceable></literal></term>
160
Only announce the server and listen to requests on network
161
interface <replaceable>IF</replaceable>. Default is to
162
use all available interfaces.
168
<term><literal>-a</literal>, <literal>--address <replaceable>
169
ADDRESS</replaceable></literal></term>
172
If this option is used, the server will only listen to a
173
specific address. This must currently be an IPv6 address;
174
an IPv4 address can be specified using the
175
"<literal>::FFFF:192.0.2.3</literal>" syntax. Also, if a
176
link-local address is specified, an interface should be
177
set, since a link-local address is only valid on a single
178
interface. By default, the server will listen to all
185
<term><literal>-p</literal>, <literal>--port <replaceable>
186
PORT</replaceable></literal></term>
189
If this option is used, the server to bind to that
190
port. By default, the server will listen to an arbitrary
191
port given by the operating system.
197
<term><literal>--check</literal></term>
200
Run the server's self-tests. This includes any unit
176
<term><option>--interface</option>
177
<replaceable>NAME</replaceable></term>
178
<term><option>-i</option>
179
<replaceable>NAME</replaceable></term>
181
<xi:include href="mandos-options.xml" xpointer="interface"/>
186
<term><option>--address
187
<replaceable>ADDRESS</replaceable></option></term>
189
<replaceable>ADDRESS</replaceable></option></term>
191
<xi:include href="mandos-options.xml" xpointer="address"/>
197
<replaceable>PORT</replaceable></option></term>
199
<replaceable>PORT</replaceable></option></term>
201
<xi:include href="mandos-options.xml" xpointer="port"/>
206
<term><option>--check</option></term>
209
Run the server’s self-tests. This includes any unit
207
<term><literal>--debug</literal></term>
210
If the server is run in debug mode, it will run in the
211
foreground and print a lot of debugging information. The
212
default is <emphasis>not</emphasis> to run in debug mode.
218
<term><literal>--priority <replaceable>
219
PRIORITY</replaceable></literal></term>
222
GnuTLS priority string for the TLS handshake with the
224
<citerefentry><refentrytitle>gnutls_priority_init
225
</refentrytitle><manvolnum>3</manvolnum></citerefentry>
226
for the syntax. The default is
227
"<literal>SECURE256:!CTYPE-X.509:+CTYPE-OPENPGP</literal>".
228
<emphasis>Warning</emphasis>: changing this may make the
229
TLS handshake fail, making communication with clients
236
<term><literal>--servicename <replaceable>NAME</replaceable>
240
Zeroconf service name. The default is
241
"<literal>Mandos</literal>". You only need to change this
242
if you for some reason want to run more than one server on
243
the same <emphasis>host</emphasis>. If there are name
244
collisions on the same <emphasis>network</emphasis>, the
245
new server will automatically rename itself to "Mandos
252
<term><literal>--configdir <replaceable>DIR</replaceable>
216
<term><option>--debug</option></term>
218
<xi:include href="mandos-options.xml" xpointer="debug"/>
223
<term><option>--debuglevel
224
<replaceable>LEVEL</replaceable></option></term>
227
Set the debugging log level.
228
<replaceable>LEVEL</replaceable> is a string, one of
229
<quote><literal>CRITICAL</literal></quote>,
230
<quote><literal>ERROR</literal></quote>,
231
<quote><literal>WARNING</literal></quote>,
232
<quote><literal>INFO</literal></quote>, or
233
<quote><literal>DEBUG</literal></quote>, in order of
234
increasing verbosity. The default level is
235
<quote><literal>WARNING</literal></quote>.
241
<term><option>--priority <replaceable>
242
PRIORITY</replaceable></option></term>
244
<xi:include href="mandos-options.xml" xpointer="priority"/>
249
<term><option>--servicename
250
<replaceable>NAME</replaceable></option></term>
252
<xi:include href="mandos-options.xml"
253
xpointer="servicename"/>
258
<term><option>--configdir
259
<replaceable>DIRECTORY</replaceable></option></term>
256
262
Directory to search for configuration files. Default is
257
"<literal>/etc/mandos</literal>". See <citerefentry>
258
<refentrytitle>mandos.conf</refentrytitle>
263
<quote><literal>/etc/mandos</literal></quote>. See
264
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
259
265
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
260
266
<refentrytitle>mandos-clients.conf</refentrytitle>
261
267
<manvolnum>5</manvolnum></citerefentry>.
267
<term><literal>--version</literal></term>
273
<term><option>--version</option></term>
270
276
Prints the program version and exit.
282
<term><option>--no-dbus</option></term>
284
<xi:include href="mandos-options.xml" xpointer="dbus"/>
286
See also <xref linkend="dbus_interface"/>.
292
<term><option>--no-ipv6</option></term>
294
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
299
<term><option>--no-restore</option></term>
301
<xi:include href="mandos-options.xml" xpointer="restore"/>
303
See also <xref linkend="persistent_state"/>.
309
<term><option>--statedir
310
<replaceable>DIRECTORY</replaceable></option></term>
312
<xi:include href="mandos-options.xml" xpointer="statedir"/>
317
<term><option>--socket
318
<replaceable>FD</replaceable></option></term>
320
<xi:include href="mandos-options.xml" xpointer="socket"/>
325
<term><option>--foreground</option></term>
327
<xi:include href="mandos-options.xml"
328
xpointer="foreground"/>
333
<term><option>--no-zeroconf</option></term>
335
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
342
<refsect1 id="overview">
343
<title>OVERVIEW</title>
344
<xi:include href="overview.xml"/>
346
This program is the server part. It is a normal server program
347
and will run in a normal system environment, not in an initial
348
<acronym>RAM</acronym> disk environment.
277
352
<refsect1 id="protocol">
278
353
<title>NETWORK PROTOCOL</title>
280
355
The Mandos server announces itself as a Zeroconf service of type
281
"<literal>_mandos._tcp</literal>". The Mandos client connects
282
to the announced address and port, and sends a line of text
283
where the first whitespace-separated field is the protocol
284
version, which currently is "<literal>1</literal>". The client
285
and server then start a TLS protocol handshake with a slight
286
quirk: the Mandos server program acts as a TLS "client" while
287
the connecting Mandos client acts as a TLS "server". The Mandos
288
client must supply an OpenPGP certificate, and the fingerprint
289
of this certificate is used by the Mandos server to look up (in
290
a list read from a file at start time) which binary blob to give
291
the client. No other authentication or authorization is done by
356
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
357
client connects to the announced address and port, and sends a
358
line of text where the first whitespace-separated field is the
359
protocol version, which currently is
360
<quote><literal>1</literal></quote>. The client and server then
361
start a TLS protocol handshake with a slight quirk: the Mandos
362
server program acts as a TLS <quote>client</quote> while the
363
connecting Mandos client acts as a TLS <quote>server</quote>.
364
The Mandos client must supply an OpenPGP certificate, and the
365
fingerprint of this certificate is used by the Mandos server to
366
look up (in a list read from <filename>clients.conf</filename>
367
at start time) which binary blob to give the client. No other
368
authentication or authorization is done by the server.
294
<informaltable><tgroup cols="3"><thead>
371
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
296
373
<entry>Mandos Client</entry>
297
374
<entry>Direction</entry>
320
399
<entry><-<!-- ← --></entry>
321
<entry>Binary blob</entry>
400
<entry>Binary blob (client will assume OpenPGP data)</entry>
325
404
<entry><-<!-- ← --></entry>
326
405
<entry>Close</entry>
328
</tbody></tgroup></informaltable>
407
</tbody></tgroup></table>
410
<refsect1 id="checking">
411
<title>CHECKING</title>
413
The server will, by default, continually check that the clients
414
are still up. If a client has not been confirmed as being up
415
for some time, the client is assumed to be compromised and is no
416
longer eligible to receive the encrypted password. (Manual
417
intervention is required to re-enable a client.) The timeout,
418
extended timeout, checker program, and interval between checks
419
can be configured both globally and per client; see
420
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
421
<manvolnum>5</manvolnum></citerefentry>.
425
<refsect1 id="approval">
426
<title>APPROVAL</title>
428
The server can be configured to require manual approval for a
429
client before it is sent its secret. The delay to wait for such
430
approval and the default action (approve or deny) can be
431
configured both globally and per client; see <citerefentry>
432
<refentrytitle>mandos-clients.conf</refentrytitle>
433
<manvolnum>5</manvolnum></citerefentry>. By default all clients
434
will be approved immediately without delay.
437
This can be used to deny a client its secret if not manually
438
approved within a specified time. It can also be used to make
439
the server delay before giving a client its secret, allowing
440
optional manual denying of this specific client.
331
445
<refsect1 id="logging">
332
446
<title>LOGGING</title>
334
The server will log a lot of information with various severity
336
<citerefentry><refentrytitle>syslog</refentrytitle>
337
<manvolnum>8</manvolnum></citerefentry>. With the
448
The server will send log message with various severity levels to
449
<filename class="devicefile">/dev/log</filename>. With the
338
450
<option>--debug</option> option, it will log even more messages,
339
451
and also show them on the console.
455
<refsect1 id="persistent_state">
456
<title>PERSISTENT STATE</title>
458
Client settings, initially read from
459
<filename>clients.conf</filename>, are persistent across
460
restarts, and run-time changes will override settings in
461
<filename>clients.conf</filename>. However, if a setting is
462
<emphasis>changed</emphasis> (or a client added, or removed) in
463
<filename>clients.conf</filename>, this will take precedence.
467
<refsect1 id="dbus_interface">
468
<title>D-BUS INTERFACE</title>
470
The server will by default provide a D-Bus system bus interface.
471
This interface will only be accessible by the root user or a
472
Mandos-specific user, if such a user exists. For documentation
473
of the D-Bus API, see the file <filename>DBUS-API</filename>.
343
477
<refsect1 id="exit_status">
344
478
<title>EXIT STATUS</title>
347
481
critical error is encountered.
485
<refsect1 id="environment">
486
<title>ENVIRONMENT</title>
489
<term><envar>PATH</envar></term>
492
To start the configured checker (see <xref
493
linkend="checking"/>), the server uses
494
<filename>/bin/sh</filename>, which in turn uses
495
<varname>PATH</varname> to search for matching commands if
496
an absolute path is not given. See <citerefentry>
497
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
505
<refsect1 id="files">
352
506
<title>FILES</title>
356
<filename>/etc/mandos/mandos.conf</filename> See <citerefentry>
357
<refentrytitle>mandos.conf</refentrytitle>
358
<manvolnum>5</manvolnum></citerefentry>.
361
<filename>/etc/mandos/clients.conf</filename> See <citerefentry>
508
Use the <option>--configdir</option> option to change where
509
<command>&COMMANDNAME;</command> looks for its configurations
510
files. The default file names are listed here.
514
<term><filename>/etc/mandos/mandos.conf</filename></term>
517
Server-global settings. See
518
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
519
<manvolnum>5</manvolnum></citerefentry> for details.
524
<term><filename>/etc/mandos/clients.conf</filename></term>
527
List of clients and client-specific settings. See
528
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
529
<manvolnum>5</manvolnum></citerefentry> for details.
534
<term><filename>/run/mandos.pid</filename></term>
537
The file containing the process id of the
538
<command>&COMMANDNAME;</command> process started last.
539
<emphasis >Note:</emphasis> If the <filename
540
class="directory">/run</filename> directory does not
541
exist, <filename>/var/run/mandos.pid</filename> will be
548
class="directory">/var/lib/mandos</filename></term>
551
Directory where persistent state will be saved. Change
552
this with the <option>--statedir</option> option. See
553
also the <option>--no-restore</option> option.
558
<term><filename class="devicefile">/dev/log</filename></term>
561
The Unix domain socket to where local syslog messages are
567
<term><filename>/bin/sh</filename></term>
570
This is used to start the configured checker command for
571
each client. See <citerefentry>
362
572
<refentrytitle>mandos-clients.conf</refentrytitle>
363
<manvolnum>5</manvolnum></citerefentry>.
366
<filename>/var/run/mandos/mandos.pid</filename>
573
<manvolnum>5</manvolnum></citerefentry> for details.
372
580
<refsect1 id="bugs">
373
581
<title>BUGS</title>
378
<refsect1 id="examples">
379
<title>EXAMPLES</title>
583
This server might, on especially fatal errors, emit a Python
584
backtrace. This could be considered a feature.
587
There is no fine-grained control over logging and debug output.
590
This server does not check the expire time of clients’ OpenPGP
593
<xi:include href="bugs.xml"/>
596
<refsect1 id="example">
597
<title>EXAMPLE</title>
600
Normal invocation needs no options:
603
<userinput>&COMMANDNAME;</userinput>
608
Run the server in debug mode, read configuration files from
609
the <filename class="directory">~/mandos</filename> directory,
610
and use the Zeroconf service name <quote>Test</quote> to not
611
collide with any other official Mandos server on this host:
615
<!-- do not wrap this line -->
616
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
622
Run the server normally, but only listen to one interface and
623
only on the link-local address on that interface:
627
<!-- do not wrap this line -->
628
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
384
634
<refsect1 id="security">
385
635
<title>SECURITY</title>
636
<refsect2 id="server">
637
<title>SERVER</title>
639
Running this <command>&COMMANDNAME;</command> server program
640
should not in itself present any security risk to the host
641
computer running it. The program switches to a non-root user
645
<refsect2 id="clients">
646
<title>CLIENTS</title>
648
The server only gives out its stored data to clients which
649
does have the OpenPGP key of the stored fingerprint. This is
650
guaranteed by the fact that the client sends its OpenPGP
651
public key in the TLS handshake; this ensures it to be
652
genuine. The server computes the fingerprint of the key
653
itself and looks up the fingerprint in its list of
654
clients. The <filename>clients.conf</filename> file (see
655
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
656
<manvolnum>5</manvolnum></citerefentry>)
657
<emphasis>must</emphasis> be made non-readable by anyone
658
except the user starting the server (usually root).
661
As detailed in <xref linkend="checking"/>, the status of all
662
client computers will continually be checked and be assumed
663
compromised if they are gone for too long.
666
For more details on client-side security, see
667
<citerefentry><refentrytitle>mandos-client</refentrytitle>
668
<manvolnum>8mandos</manvolnum></citerefentry>.
390
673
<refsect1 id="see_also">
391
674
<title>SEE ALSO</title>
392
<itemizedlist spacing="compact">
394
<citerefentry><refentrytitle>password-request</refentrytitle>
395
<manvolnum>8mandos</manvolnum></citerefentry>
399
<citerefentry><refentrytitle>plugin-runner</refentrytitle>
400
<manvolnum>8mandos</manvolnum></citerefentry>
404
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
408
<ulink url="http://www.avahi.org/">Avahi</ulink>
413
url="http://www.gnu.org/software/gnutls/">GnuTLS</ulink>
417
<citation>RFC 4880: <citetitle>OpenPGP Message
418
Format</citetitle></citation>
422
<citation>RFC 5081: <citetitle>Using OpenPGP Keys for
423
Transport Layer Security</citetitle></citation>
427
<citation>RFC 4291: <citetitle>IP Version 6 Addressing
428
Architecture</citetitle>, section 2.5.6, Link-Local IPv6
429
Unicast Addresses</citation>
676
<citerefentry><refentrytitle>intro</refentrytitle>
677
<manvolnum>8mandos</manvolnum></citerefentry>,
678
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
679
<manvolnum>5</manvolnum></citerefentry>,
680
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
681
<manvolnum>5</manvolnum></citerefentry>,
682
<citerefentry><refentrytitle>mandos-client</refentrytitle>
683
<manvolnum>8mandos</manvolnum></citerefentry>,
684
<citerefentry><refentrytitle>sh</refentrytitle>
685
<manvolnum>1</manvolnum></citerefentry>
690
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
694
Zeroconf is the network protocol standard used by clients
695
for finding this Mandos server on the local network.
701
<ulink url="http://www.avahi.org/">Avahi</ulink>
705
Avahi is the library this server calls to implement
706
Zeroconf service announcements.
712
<ulink url="https://gnutls.org/">GnuTLS</ulink>
716
GnuTLS is the library this server uses to implement TLS for
717
communicating securely with the client, and at the same time
718
confidently get the client’s public OpenPGP key.
724
RFC 4291: <citetitle>IP Version 6 Addressing
725
Architecture</citetitle>
730
<term>Section 2.2: <citetitle>Text Representation of
731
Addresses</citetitle></term>
732
<listitem><para/></listitem>
735
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
736
Address</citetitle></term>
737
<listitem><para/></listitem>
740
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
741
Addresses</citetitle></term>
744
The clients use IPv6 link-local addresses, which are
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immediately usable since a link-local addresses is
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automatically assigned to a network interfaces when it
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RFC 5246: <citetitle>The Transport Layer Security (TLS)
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Protocol Version 1.2</citetitle>
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TLS 1.2 is the protocol implemented by GnuTLS.
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RFC 4880: <citetitle>OpenPGP Message Format</citetitle>
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The data sent to clients is binary encrypted OpenPGP data.
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RFC 6091: <citetitle>Using OpenPGP Keys for Transport Layer
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Security (TLS) Authentication</citetitle>
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This is implemented by GnuTLS and used by this server so
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that OpenPGP keys can be used.
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