68
54
<refname><command>&COMMANDNAME;</command></refname>
70
Sends encrypted passwords to authenticated Mandos clients
56
Gives encrypted passwords to authenticated Mandos clients
76
62
<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>
64
<arg choice="plain"><option>--interface
65
<replaceable>NAME</replaceable></option></arg>
66
<arg choice="plain"><option>-i
67
<replaceable>NAME</replaceable></option></arg>
71
<arg choice="plain"><option>--address
72
<replaceable>ADDRESS</replaceable></option></arg>
73
<arg choice="plain"><option>-a
74
<replaceable>ADDRESS</replaceable></option></arg>
78
<arg choice="plain"><option>--port
79
<replaceable>PORT</replaceable></option></arg>
80
<arg choice="plain"><option>-p
81
<replaceable>PORT</replaceable></option></arg>
84
<arg><option>--priority
85
<replaceable>PRIORITY</replaceable></option></arg>
87
<arg><option>--servicename
88
<replaceable>NAME</replaceable></option></arg>
90
<arg><option>--configdir
91
<replaceable>DIRECTORY</replaceable></option></arg>
93
<arg><option>--debug</option></arg>
95
<arg><option>--debuglevel
96
<replaceable>LEVEL</replaceable></option></arg>
98
<arg><option>--no-dbus</option></arg>
100
<arg><option>--no-ipv6</option></arg>
102
<arg><option>--no-restore</option></arg>
104
<arg><option>--statedir
105
<replaceable>DIRECTORY</replaceable></option></arg>
107
<arg><option>--socket
108
<replaceable>FD</replaceable></option></arg>
110
<arg><option>--foreground</option></arg>
112
<arg><option>--no-zeroconf</option></arg>
115
<command>&COMMANDNAME;</command>
117
<arg choice="plain"><option>--help</option></arg>
118
<arg choice="plain"><option>-h</option></arg>
122
<command>&COMMANDNAME;</command>
123
<arg choice="plain"><option>--version</option></arg>
126
<command>&COMMANDNAME;</command>
127
<arg choice="plain"><option>--check</option></arg>
107
129
</refsynopsisdiv>
109
131
<refsect1 id="description">
110
132
<title>DESCRIPTION</title>
112
134
<command>&COMMANDNAME;</command> is a server daemon which
113
135
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.
136
client host computers. For an introduction, see
137
<citerefentry><refentrytitle>intro</refentrytitle>
138
<manvolnum>8mandos</manvolnum></citerefentry>. The Mandos server
139
uses Zeroconf to announce itself on the local network, and uses
140
TLS to communicate securely with and to authenticate the
141
clients. The Mandos server uses IPv6 to allow Mandos clients to
142
use IPv6 link-local addresses, since the clients will probably
143
not have any other addresses configured (see <xref
144
linkend="overview"/>). Any authenticated client is then given
145
the stored pre-encrypted password for that specific client.
125
149
<refsect1 id="purpose">
126
150
<title>PURPOSE</title>
129
152
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
153
rebooting</emphasis> of client host computer with an
154
<emphasis>encrypted root file system</emphasis>. See <xref
155
linkend="overview"/> for details.
142
159
<refsect1 id="options">
143
160
<title>OPTIONS</title>
147
<term><literal>-h</literal>, <literal>--help</literal></term>
163
<term><option>--help</option></term>
164
<term><option>-h</option></term>
150
167
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
173
<term><option>--interface</option>
174
<replaceable>NAME</replaceable></term>
175
<term><option>-i</option>
176
<replaceable>NAME</replaceable></term>
178
<xi:include href="mandos-options.xml" xpointer="interface"/>
183
<term><option>--address
184
<replaceable>ADDRESS</replaceable></option></term>
186
<replaceable>ADDRESS</replaceable></option></term>
188
<xi:include href="mandos-options.xml" xpointer="address"/>
194
<replaceable>PORT</replaceable></option></term>
196
<replaceable>PORT</replaceable></option></term>
198
<xi:include href="mandos-options.xml" xpointer="port"/>
203
<term><option>--check</option></term>
206
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>
213
<term><option>--debug</option></term>
215
<xi:include href="mandos-options.xml" xpointer="debug"/>
220
<term><option>--debuglevel
221
<replaceable>LEVEL</replaceable></option></term>
224
Set the debugging log level.
225
<replaceable>LEVEL</replaceable> is a string, one of
226
<quote><literal>CRITICAL</literal></quote>,
227
<quote><literal>ERROR</literal></quote>,
228
<quote><literal>WARNING</literal></quote>,
229
<quote><literal>INFO</literal></quote>, or
230
<quote><literal>DEBUG</literal></quote>, in order of
231
increasing verbosity. The default level is
232
<quote><literal>WARNING</literal></quote>.
238
<term><option>--priority <replaceable>
239
PRIORITY</replaceable></option></term>
241
<xi:include href="mandos-options.xml" xpointer="priority"/>
246
<term><option>--servicename
247
<replaceable>NAME</replaceable></option></term>
249
<xi:include href="mandos-options.xml"
250
xpointer="servicename"/>
255
<term><option>--configdir
256
<replaceable>DIRECTORY</replaceable></option></term>
256
259
Directory to search for configuration files. Default is
257
"<literal>/etc/mandos</literal>". See <citerefentry>
258
<refentrytitle>mandos.conf</refentrytitle>
260
<quote><literal>/etc/mandos</literal></quote>. See
261
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
259
262
<manvolnum>5</manvolnum></citerefentry> and <citerefentry>
260
263
<refentrytitle>mandos-clients.conf</refentrytitle>
261
264
<manvolnum>5</manvolnum></citerefentry>.
267
<term><literal>--version</literal></term>
270
<term><option>--version</option></term>
270
273
Prints the program version and exit.
279
<term><option>--no-dbus</option></term>
281
<xi:include href="mandos-options.xml" xpointer="dbus"/>
283
See also <xref linkend="dbus_interface"/>.
289
<term><option>--no-ipv6</option></term>
291
<xi:include href="mandos-options.xml" xpointer="ipv6"/>
296
<term><option>--no-restore</option></term>
298
<xi:include href="mandos-options.xml" xpointer="restore"/>
300
See also <xref linkend="persistent_state"/>.
306
<term><option>--statedir
307
<replaceable>DIRECTORY</replaceable></option></term>
309
<xi:include href="mandos-options.xml" xpointer="statedir"/>
314
<term><option>--socket
315
<replaceable>FD</replaceable></option></term>
317
<xi:include href="mandos-options.xml" xpointer="socket"/>
322
<term><option>--foreground</option></term>
324
<xi:include href="mandos-options.xml"
325
xpointer="foreground"/>
330
<term><option>--no-zeroconf</option></term>
332
<xi:include href="mandos-options.xml" xpointer="zeroconf"/>
339
<refsect1 id="overview">
340
<title>OVERVIEW</title>
341
<xi:include href="overview.xml"/>
343
This program is the server part. It is a normal server program
344
and will run in a normal system environment, not in an initial
345
<acronym>RAM</acronym> disk environment.
277
349
<refsect1 id="protocol">
278
350
<title>NETWORK PROTOCOL</title>
280
352
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
353
<quote><literal>_mandos._tcp</literal></quote>. The Mandos
354
client connects to the announced address and port, and sends a
355
line of text where the first whitespace-separated field is the
356
protocol version, which currently is
357
<quote><literal>1</literal></quote>. The client and server then
358
start a TLS protocol handshake with a slight quirk: the Mandos
359
server program acts as a TLS <quote>client</quote> while the
360
connecting Mandos client acts as a TLS <quote>server</quote>.
361
The Mandos client must supply an OpenPGP certificate, and the
362
fingerprint of this certificate is used by the Mandos server to
363
look up (in a list read from <filename>clients.conf</filename>
364
at start time) which binary blob to give the client. No other
365
authentication or authorization is done by the server.
294
<informaltable><tgroup cols="3"><thead>
368
<title>Mandos Protocol (Version 1)</title><tgroup cols="3"><thead>
296
370
<entry>Mandos Client</entry>
297
371
<entry>Direction</entry>
320
396
<entry><-<!-- ← --></entry>
321
<entry>Binary blob</entry>
397
<entry>Binary blob (client will assume OpenPGP data)</entry>
325
401
<entry><-<!-- ← --></entry>
326
402
<entry>Close</entry>
328
</tbody></tgroup></informaltable>
404
</tbody></tgroup></table>
407
<refsect1 id="checking">
408
<title>CHECKING</title>
410
The server will, by default, continually check that the clients
411
are still up. If a client has not been confirmed as being up
412
for some time, the client is assumed to be compromised and is no
413
longer eligible to receive the encrypted password. (Manual
414
intervention is required to re-enable a client.) The timeout,
415
extended timeout, checker program, and interval between checks
416
can be configured both globally and per client; see
417
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
418
<manvolnum>5</manvolnum></citerefentry>.
422
<refsect1 id="approval">
423
<title>APPROVAL</title>
425
The server can be configured to require manual approval for a
426
client before it is sent its secret. The delay to wait for such
427
approval and the default action (approve or deny) can be
428
configured both globally and per client; see <citerefentry>
429
<refentrytitle>mandos-clients.conf</refentrytitle>
430
<manvolnum>5</manvolnum></citerefentry>. By default all clients
431
will be approved immediately without delay.
434
This can be used to deny a client its secret if not manually
435
approved within a specified time. It can also be used to make
436
the server delay before giving a client its secret, allowing
437
optional manual denying of this specific client.
331
442
<refsect1 id="logging">
332
443
<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
445
The server will send log message with various severity levels to
446
<filename class="devicefile">/dev/log</filename>. With the
338
447
<option>--debug</option> option, it will log even more messages,
339
448
and also show them on the console.
452
<refsect1 id="persistent_state">
453
<title>PERSISTENT STATE</title>
455
Client settings, initially read from
456
<filename>clients.conf</filename>, are persistent across
457
restarts, and run-time changes will override settings in
458
<filename>clients.conf</filename>. However, if a setting is
459
<emphasis>changed</emphasis> (or a client added, or removed) in
460
<filename>clients.conf</filename>, this will take precedence.
464
<refsect1 id="dbus_interface">
465
<title>D-BUS INTERFACE</title>
467
The server will by default provide a D-Bus system bus interface.
468
This interface will only be accessible by the root user or a
469
Mandos-specific user, if such a user exists. For documentation
470
of the D-Bus API, see the file <filename>DBUS-API</filename>.
343
474
<refsect1 id="exit_status">
344
475
<title>EXIT STATUS</title>
347
478
critical error is encountered.
482
<refsect1 id="environment">
483
<title>ENVIRONMENT</title>
486
<term><envar>PATH</envar></term>
489
To start the configured checker (see <xref
490
linkend="checking"/>), the server uses
491
<filename>/bin/sh</filename>, which in turn uses
492
<varname>PATH</varname> to search for matching commands if
493
an absolute path is not given. See <citerefentry>
494
<refentrytitle>sh</refentrytitle><manvolnum>1</manvolnum>
502
<refsect1 id="files">
352
503
<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>
505
Use the <option>--configdir</option> option to change where
506
<command>&COMMANDNAME;</command> looks for its configurations
507
files. The default file names are listed here.
511
<term><filename>/etc/mandos/mandos.conf</filename></term>
514
Server-global settings. See
515
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
516
<manvolnum>5</manvolnum></citerefentry> for details.
521
<term><filename>/etc/mandos/clients.conf</filename></term>
524
List of clients and client-specific settings. See
525
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
526
<manvolnum>5</manvolnum></citerefentry> for details.
531
<term><filename>/run/mandos.pid</filename></term>
534
The file containing the process id of the
535
<command>&COMMANDNAME;</command> process started last.
536
<emphasis >Note:</emphasis> If the <filename
537
class="directory">/run</filename> directory does not
538
exist, <filename>/var/run/mandos.pid</filename> will be
544
<term><filename class="devicefile">/dev/log</filename></term>
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>/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
595
<refsect1 id="example">
596
<title>EXAMPLE</title>
599
Normal invocation needs no options:
602
<userinput>&COMMANDNAME;</userinput>
607
Run the server in debug mode, read configuration files from
608
the <filename class="directory">~/mandos</filename> directory,
609
and use the Zeroconf service name <quote>Test</quote> to not
610
collide with any other official Mandos server on this host:
614
<!-- do not wrap this line -->
615
<userinput>&COMMANDNAME; --debug --configdir ~/mandos --servicename Test</userinput>
621
Run the server normally, but only listen to one interface and
622
only on the link-local address on that interface:
626
<!-- do not wrap this line -->
627
<userinput>&COMMANDNAME; --interface eth7 --address fe80::aede:48ff:fe71:f6f2</userinput>
384
633
<refsect1 id="security">
385
634
<title>SECURITY</title>
635
<refsect2 id="server">
636
<title>SERVER</title>
638
Running this <command>&COMMANDNAME;</command> server program
639
should not in itself present any security risk to the host
640
computer running it. The program switches to a non-root user
644
<refsect2 id="clients">
645
<title>CLIENTS</title>
647
The server only gives out its stored data to clients which
648
does have the OpenPGP key of the stored fingerprint. This is
649
guaranteed by the fact that the client sends its OpenPGP
650
public key in the TLS handshake; this ensures it to be
651
genuine. The server computes the fingerprint of the key
652
itself and looks up the fingerprint in its list of
653
clients. The <filename>clients.conf</filename> file (see
654
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
655
<manvolnum>5</manvolnum></citerefentry>)
656
<emphasis>must</emphasis> be made non-readable by anyone
657
except the user starting the server (usually root).
660
As detailed in <xref linkend="checking"/>, the status of all
661
client computers will continually be checked and be assumed
662
compromised if they are gone for too long.
665
For more details on client-side security, see
666
<citerefentry><refentrytitle>mandos-client</refentrytitle>
667
<manvolnum>8mandos</manvolnum></citerefentry>.
390
672
<refsect1 id="see_also">
391
673
<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>
675
<citerefentry><refentrytitle>intro</refentrytitle>
676
<manvolnum>8mandos</manvolnum></citerefentry>,
677
<citerefentry><refentrytitle>mandos-clients.conf</refentrytitle>
678
<manvolnum>5</manvolnum></citerefentry>,
679
<citerefentry><refentrytitle>mandos.conf</refentrytitle>
680
<manvolnum>5</manvolnum></citerefentry>,
681
<citerefentry><refentrytitle>mandos-client</refentrytitle>
682
<manvolnum>8mandos</manvolnum></citerefentry>,
683
<citerefentry><refentrytitle>sh</refentrytitle>
684
<manvolnum>1</manvolnum></citerefentry>
689
<ulink url="http://www.zeroconf.org/">Zeroconf</ulink>
693
Zeroconf is the network protocol standard used by clients
694
for finding this Mandos server on the local network.
700
<ulink url="http://www.avahi.org/">Avahi</ulink>
704
Avahi is the library this server calls to implement
705
Zeroconf service announcements.
711
<ulink url="http://gnutls.org/">GnuTLS</ulink>
715
GnuTLS is the library this server uses to implement TLS for
716
communicating securely with the client, and at the same time
717
confidently get the client’s public OpenPGP key.
723
RFC 4291: <citetitle>IP Version 6 Addressing
724
Architecture</citetitle>
729
<term>Section 2.2: <citetitle>Text Representation of
730
Addresses</citetitle></term>
731
<listitem><para/></listitem>
734
<term>Section 2.5.5.2: <citetitle>IPv4-Mapped IPv6
735
Address</citetitle></term>
736
<listitem><para/></listitem>
739
<term>Section 2.5.6, <citetitle>Link-Local IPv6 Unicast
740
Addresses</citetitle></term>
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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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