summaryrefslogtreecommitdiffstats
path: root/secure/usr.bin/openssl/man/s_server.1
blob: dc951e0357ad37b37f27d12c67d75dfab9ca2cff (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
.\" Automatically generated by Pod::Man 2.28 (Pod::Simple 3.28)
.\"
.\" Standard preamble:
.\" ========================================================================
.de Sp \" Vertical space (when we can't use .PP)
.if t .sp .5v
.if n .sp
..
.de Vb \" Begin verbatim text
.ft CW
.nf
.ne \\$1
..
.de Ve \" End verbatim text
.ft R
.fi
..
.\" Set up some character translations and predefined strings.  \*(-- will
.\" give an unbreakable dash, \*(PI will give pi, \*(L" will give a left
.\" double quote, and \*(R" will give a right double quote.  \*(C+ will
.\" give a nicer C++.  Capital omega is used to do unbreakable dashes and
.\" therefore won't be available.  \*(C` and \*(C' expand to `' in nroff,
.\" nothing in troff, for use with C<>.
.tr \(*W-
.ds C+ C\v'-.1v'\h'-1p'\s-2+\h'-1p'+\s0\v'.1v'\h'-1p'
.ie n \{\
.    ds -- \(*W-
.    ds PI pi
.    if (\n(.H=4u)&(1m=24u) .ds -- \(*W\h'-12u'\(*W\h'-12u'-\" diablo 10 pitch
.    if (\n(.H=4u)&(1m=20u) .ds -- \(*W\h'-12u'\(*W\h'-8u'-\"  diablo 12 pitch
.    ds L" ""
.    ds R" ""
.    ds C` ""
.    ds C' ""
'br\}
.el\{\
.    ds -- \|\(em\|
.    ds PI \(*p
.    ds L" ``
.    ds R" ''
.    ds C`
.    ds C'
'br\}
.\"
.\" Escape single quotes in literal strings from groff's Unicode transform.
.ie \n(.g .ds Aq \(aq
.el       .ds Aq '
.\"
.\" If the F register is turned on, we'll generate index entries on stderr for
.\" titles (.TH), headers (.SH), subsections (.SS), items (.Ip), and index
.\" entries marked with X<> in POD.  Of course, you'll have to process the
.\" output yourself in some meaningful fashion.
.\"
.\" Avoid warning from groff about undefined register 'F'.
.de IX
..
.nr rF 0
.if \n(.g .if rF .nr rF 1
.if (\n(rF:(\n(.g==0)) \{
.    if \nF \{
.        de IX
.        tm Index:\\$1\t\\n%\t"\\$2"
..
.        if !\nF==2 \{
.            nr % 0
.            nr F 2
.        \}
.    \}
.\}
.rr rF
.\"
.\" Accent mark definitions (@(#)ms.acc 1.5 88/02/08 SMI; from UCB 4.2).
.\" Fear.  Run.  Save yourself.  No user-serviceable parts.
.    \" fudge factors for nroff and troff
.if n \{\
.    ds #H 0
.    ds #V .8m
.    ds #F .3m
.    ds #[ \f1
.    ds #] \fP
.\}
.if t \{\
.    ds #H ((1u-(\\\\n(.fu%2u))*.13m)
.    ds #V .6m
.    ds #F 0
.    ds #[ \&
.    ds #] \&
.\}
.    \" simple accents for nroff and troff
.if n \{\
.    ds ' \&
.    ds ` \&
.    ds ^ \&
.    ds , \&
.    ds ~ ~
.    ds /
.\}
.if t \{\
.    ds ' \\k:\h'-(\\n(.wu*8/10-\*(#H)'\'\h"|\\n:u"
.    ds ` \\k:\h'-(\\n(.wu*8/10-\*(#H)'\`\h'|\\n:u'
.    ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'^\h'|\\n:u'
.    ds , \\k:\h'-(\\n(.wu*8/10)',\h'|\\n:u'
.    ds ~ \\k:\h'-(\\n(.wu-\*(#H-.1m)'~\h'|\\n:u'
.    ds / \\k:\h'-(\\n(.wu*8/10-\*(#H)'\z\(sl\h'|\\n:u'
.\}
.    \" troff and (daisy-wheel) nroff accents
.ds : \\k:\h'-(\\n(.wu*8/10-\*(#H+.1m+\*(#F)'\v'-\*(#V'\z.\h'.2m+\*(#F'.\h'|\\n:u'\v'\*(#V'
.ds 8 \h'\*(#H'\(*b\h'-\*(#H'
.ds o \\k:\h'-(\\n(.wu+\w'\(de'u-\*(#H)/2u'\v'-.3n'\*(#[\z\(de\v'.3n'\h'|\\n:u'\*(#]
.ds d- \h'\*(#H'\(pd\h'-\w'~'u'\v'-.25m'\f2\(hy\fP\v'.25m'\h'-\*(#H'
.ds D- D\\k:\h'-\w'D'u'\v'-.11m'\z\(hy\v'.11m'\h'|\\n:u'
.ds th \*(#[\v'.3m'\s+1I\s-1\v'-.3m'\h'-(\w'I'u*2/3)'\s-1o\s+1\*(#]
.ds Th \*(#[\s+2I\s-2\h'-\w'I'u*3/5'\v'-.3m'o\v'.3m'\*(#]
.ds ae a\h'-(\w'a'u*4/10)'e
.ds Ae A\h'-(\w'A'u*4/10)'E
.    \" corrections for vroff
.if v .ds ~ \\k:\h'-(\\n(.wu*9/10-\*(#H)'\s-2\u~\d\s+2\h'|\\n:u'
.if v .ds ^ \\k:\h'-(\\n(.wu*10/11-\*(#H)'\v'-.4m'^\v'.4m'\h'|\\n:u'
.    \" for low resolution devices (crt and lpr)
.if \n(.H>23 .if \n(.V>19 \
\{\
.    ds : e
.    ds 8 ss
.    ds o a
.    ds d- d\h'-1'\(ga
.    ds D- D\h'-1'\(hy
.    ds th \o'bp'
.    ds Th \o'LP'
.    ds ae ae
.    ds Ae AE
.\}
.rm #[ #] #H #V #F C
.\" ========================================================================
.\"
.IX Title "S_SERVER 1"
.TH S_SERVER 1 "2016-09-22" "1.0.2i" "OpenSSL"
.\" For nroff, turn off justification.  Always turn off hyphenation; it makes
.\" way too many mistakes in technical documents.
.if n .ad l
.nh
.SH "NAME"
s_server \- SSL/TLS server program
.SH "SYNOPSIS"
.IX Header "SYNOPSIS"
\&\fBopenssl\fR \fBs_server\fR
[\fB\-accept port\fR]
[\fB\-context id\fR]
[\fB\-verify depth\fR]
[\fB\-Verify depth\fR]
[\fB\-crl_check\fR]
[\fB\-crl_check_all\fR]
[\fB\-cert filename\fR]
[\fB\-certform DER|PEM\fR]
[\fB\-key keyfile\fR]
[\fB\-keyform DER|PEM\fR]
[\fB\-pass arg\fR]
[\fB\-dcert filename\fR]
[\fB\-dcertform DER|PEM\fR]
[\fB\-dkey keyfile\fR]
[\fB\-dkeyform DER|PEM\fR]
[\fB\-dpass arg\fR]
[\fB\-dhparam filename\fR]
[\fB\-nbio\fR]
[\fB\-nbio_test\fR]
[\fB\-crlf\fR]
[\fB\-debug\fR]
[\fB\-msg\fR]
[\fB\-state\fR]
[\fB\-CApath directory\fR]
[\fB\-CAfile filename\fR]
[\fB\-no_alt_chains\fR]
[\fB\-nocert\fR]
[\fB\-cipher cipherlist\fR]
[\fB\-serverpref\fR]
[\fB\-quiet\fR]
[\fB\-no_tmp_rsa\fR]
[\fB\-ssl2\fR]
[\fB\-ssl3\fR]
[\fB\-tls1\fR]
[\fB\-no_ssl2\fR]
[\fB\-no_ssl3\fR]
[\fB\-no_tls1\fR]
[\fB\-no_dhe\fR]
[\fB\-bugs\fR]
[\fB\-hack\fR]
[\fB\-www\fR]
[\fB\-WWW\fR]
[\fB\-HTTP\fR]
[\fB\-engine id\fR]
[\fB\-tlsextdebug\fR]
[\fB\-no_ticket\fR]
[\fB\-id_prefix arg\fR]
[\fB\-rand file(s)\fR]
[\fB\-serverinfo file\fR]
[\fB\-no_resumption_on_reneg\fR]
[\fB\-status\fR]
[\fB\-status_verbose\fR]
[\fB\-status_timeout nsec\fR]
[\fB\-status_url url\fR]
[\fB\-alpn protocols\fR]
[\fB\-nextprotoneg protocols\fR]
.SH "DESCRIPTION"
.IX Header "DESCRIPTION"
The \fBs_server\fR command implements a generic \s-1SSL/TLS\s0 server which listens
for connections on a given port using \s-1SSL/TLS.\s0
.SH "OPTIONS"
.IX Header "OPTIONS"
.IP "\fB\-accept port\fR" 4
.IX Item "-accept port"
the \s-1TCP\s0 port to listen on for connections. If not specified 4433 is used.
.IP "\fB\-context id\fR" 4
.IX Item "-context id"
sets the \s-1SSL\s0 context id. It can be given any string value. If this option
is not present a default value will be used.
.IP "\fB\-cert certname\fR" 4
.IX Item "-cert certname"
The certificate to use, most servers cipher suites require the use of a
certificate and some require a certificate with a certain public key type:
for example the \s-1DSS\s0 cipher suites require a certificate containing a \s-1DSS
\&\s0(\s-1DSA\s0) key. If not specified then the filename \*(L"server.pem\*(R" will be used.
.IP "\fB\-certform format\fR" 4
.IX Item "-certform format"
The certificate format to use: \s-1DER\s0 or \s-1PEM. PEM\s0 is the default.
.IP "\fB\-key keyfile\fR" 4
.IX Item "-key keyfile"
The private key to use. If not specified then the certificate file will
be used.
.IP "\fB\-keyform format\fR" 4
.IX Item "-keyform format"
The private format to use: \s-1DER\s0 or \s-1PEM. PEM\s0 is the default.
.IP "\fB\-pass arg\fR" 4
.IX Item "-pass arg"
the private key password source. For more information about the format of \fBarg\fR
see the \fB\s-1PASS PHRASE ARGUMENTS\s0\fR section in \fIopenssl\fR\|(1).
.IP "\fB\-dcert filename\fR, \fB\-dkey keyname\fR" 4
.IX Item "-dcert filename, -dkey keyname"
specify an additional certificate and private key, these behave in the
same manner as the \fB\-cert\fR and \fB\-key\fR options except there is no default
if they are not specified (no additional certificate and key is used). As
noted above some cipher suites require a certificate containing a key of
a certain type. Some cipher suites need a certificate carrying an \s-1RSA\s0 key
and some a \s-1DSS \s0(\s-1DSA\s0) key. By using \s-1RSA\s0 and \s-1DSS\s0 certificates and keys
a server can support clients which only support \s-1RSA\s0 or \s-1DSS\s0 cipher suites
by using an appropriate certificate.
.IP "\fB\-dcertform format\fR, \fB\-dkeyform format\fR, \fB\-dpass arg\fR" 4
.IX Item "-dcertform format, -dkeyform format, -dpass arg"
additional certificate and private key format and passphrase respectively.
.IP "\fB\-nocert\fR" 4
.IX Item "-nocert"
if this option is set then no certificate is used. This restricts the
cipher suites available to the anonymous ones (currently just anonymous
\&\s-1DH\s0).
.IP "\fB\-dhparam filename\fR" 4
.IX Item "-dhparam filename"
the \s-1DH\s0 parameter file to use. The ephemeral \s-1DH\s0 cipher suites generate keys
using a set of \s-1DH\s0 parameters. If not specified then an attempt is made to
load the parameters from the server certificate file. If this fails then
a static set of parameters hard coded into the s_server program will be used.
.IP "\fB\-no_dhe\fR" 4
.IX Item "-no_dhe"
if this option is set then no \s-1DH\s0 parameters will be loaded effectively
disabling the ephemeral \s-1DH\s0 cipher suites.
.IP "\fB\-no_tmp_rsa\fR" 4
.IX Item "-no_tmp_rsa"
certain export cipher suites sometimes use a temporary \s-1RSA\s0 key, this option
disables temporary \s-1RSA\s0 key generation.
.IP "\fB\-verify depth\fR, \fB\-Verify depth\fR" 4
.IX Item "-verify depth, -Verify depth"
The verify depth to use. This specifies the maximum length of the
client certificate chain and makes the server request a certificate from
the client. With the \fB\-verify\fR option a certificate is requested but the
client does not have to send one, with the \fB\-Verify\fR option the client
must supply a certificate or an error occurs.
.Sp
If the ciphersuite cannot request a client certificate (for example an
anonymous ciphersuite or \s-1PSK\s0) this option has no effect.
.IP "\fB\-crl_check\fR, \fB\-crl_check_all\fR" 4
.IX Item "-crl_check, -crl_check_all"
Check the peer certificate has not been revoked by its \s-1CA.\s0
The \s-1CRL\s0(s) are appended to the certificate file. With the \fB\-crl_check_all\fR
option all CRLs of all CAs in the chain are checked.
.IP "\fB\-CApath directory\fR" 4
.IX Item "-CApath directory"
The directory to use for client certificate verification. This directory
must be in \*(L"hash format\*(R", see \fBverify\fR for more information. These are
also used when building the server certificate chain.
.IP "\fB\-CAfile file\fR" 4
.IX Item "-CAfile file"
A file containing trusted certificates to use during client authentication
and to use when attempting to build the server certificate chain. The list
is also used in the list of acceptable client CAs passed to the client when
a certificate is requested.
.IP "\fB\-no_alt_chains\fR" 4
.IX Item "-no_alt_chains"
See the \fBverify\fR manual page for details.
.IP "\fB\-state\fR" 4
.IX Item "-state"
prints out the \s-1SSL\s0 session states.
.IP "\fB\-debug\fR" 4
.IX Item "-debug"
print extensive debugging information including a hex dump of all traffic.
.IP "\fB\-msg\fR" 4
.IX Item "-msg"
show all protocol messages with hex dump.
.IP "\fB\-nbio_test\fR" 4
.IX Item "-nbio_test"
tests non blocking I/O
.IP "\fB\-nbio\fR" 4
.IX Item "-nbio"
turns on non blocking I/O
.IP "\fB\-crlf\fR" 4
.IX Item "-crlf"
this option translated a line feed from the terminal into \s-1CR+LF.\s0
.IP "\fB\-quiet\fR" 4
.IX Item "-quiet"
inhibit printing of session and certificate information.
.IP "\fB\-psk_hint hint\fR" 4
.IX Item "-psk_hint hint"
Use the \s-1PSK\s0 identity hint \fBhint\fR when using a \s-1PSK\s0 cipher suite.
.IP "\fB\-psk key\fR" 4
.IX Item "-psk key"
Use the \s-1PSK\s0 key \fBkey\fR when using a \s-1PSK\s0 cipher suite. The key is
given as a hexadecimal number without leading 0x, for example \-psk
1a2b3c4d.
.IP "\fB\-ssl2\fR, \fB\-ssl3\fR, \fB\-tls1\fR, \fB\-tls1_1\fR, \fB\-tls1_2\fR, \fB\-no_ssl2\fR, \fB\-no_ssl3\fR, \fB\-no_tls1\fR, \fB\-no_tls1_1\fR, \fB\-no_tls1_2\fR" 4
.IX Item "-ssl2, -ssl3, -tls1, -tls1_1, -tls1_2, -no_ssl2, -no_ssl3, -no_tls1, -no_tls1_1, -no_tls1_2"
These options require or disable the use of the specified \s-1SSL\s0 or \s-1TLS\s0 protocols.
By default the initial handshake uses a \fIversion-flexible\fR method which will
negotiate the highest mutually supported protocol version.
.IP "\fB\-bugs\fR" 4
.IX Item "-bugs"
there are several known bug in \s-1SSL\s0 and \s-1TLS\s0 implementations. Adding this
option enables various workarounds.
.IP "\fB\-hack\fR" 4
.IX Item "-hack"
this option enables a further workaround for some some early Netscape
\&\s-1SSL\s0 code (?).
.IP "\fB\-cipher cipherlist\fR" 4
.IX Item "-cipher cipherlist"
this allows the cipher list used by the server to be modified.  When
the client sends a list of supported ciphers the first client cipher
also included in the server list is used. Because the client specifies
the preference order, the order of the server cipherlist irrelevant. See
the \fBciphers\fR command for more information.
.IP "\fB\-serverpref\fR" 4
.IX Item "-serverpref"
use the server's cipher preferences, rather than the client's preferences.
.IP "\fB\-tlsextdebug\fR" 4
.IX Item "-tlsextdebug"
print out a hex dump of any \s-1TLS\s0 extensions received from the server.
.IP "\fB\-no_ticket\fR" 4
.IX Item "-no_ticket"
disable RFC4507bis session ticket support.
.IP "\fB\-www\fR" 4
.IX Item "-www"
sends a status message back to the client when it connects. This includes
lots of information about the ciphers used and various session parameters.
The output is in \s-1HTML\s0 format so this option will normally be used with a
web browser.
.IP "\fB\-WWW\fR" 4
.IX Item "-WWW"
emulates a simple web server. Pages will be resolved relative to the
current directory, for example if the \s-1URL\s0 https://myhost/page.html is
requested the file ./page.html will be loaded.
.IP "\fB\-HTTP\fR" 4
.IX Item "-HTTP"
emulates a simple web server. Pages will be resolved relative to the
current directory, for example if the \s-1URL\s0 https://myhost/page.html is
requested the file ./page.html will be loaded. The files loaded are
assumed to contain a complete and correct \s-1HTTP\s0 response (lines that
are part of the \s-1HTTP\s0 response line and headers must end with \s-1CRLF\s0).
.IP "\fB\-engine id\fR" 4
.IX Item "-engine id"
specifying an engine (by its unique \fBid\fR string) will cause \fBs_server\fR
to attempt to obtain a functional reference to the specified engine,
thus initialising it if needed. The engine will then be set as the default
for all available algorithms.
.IP "\fB\-id_prefix arg\fR" 4
.IX Item "-id_prefix arg"
generate \s-1SSL/TLS\s0 session IDs prefixed by \fBarg\fR. This is mostly useful
for testing any \s-1SSL/TLS\s0 code (eg. proxies) that wish to deal with multiple
servers, when each of which might be generating a unique range of session
IDs (eg. with a certain prefix).
.IP "\fB\-rand file(s)\fR" 4
.IX Item "-rand file(s)"
a file or files containing random data used to seed the random number
generator, or an \s-1EGD\s0 socket (see \fIRAND_egd\fR\|(3)).
Multiple files can be specified separated by a OS-dependent character.
The separator is \fB;\fR for MS-Windows, \fB,\fR for OpenVMS, and \fB:\fR for
all others.
.IP "\fB\-serverinfo file\fR" 4
.IX Item "-serverinfo file"
a file containing one or more blocks of \s-1PEM\s0 data.  Each \s-1PEM\s0 block
must encode a \s-1TLS\s0 ServerHello extension (2 bytes type, 2 bytes length,
followed by \*(L"length\*(R" bytes of extension data).  If the client sends
an empty \s-1TLS\s0 ClientHello extension matching the type, the corresponding
ServerHello extension will be returned.
.IP "\fB\-no_resumption_on_reneg\fR" 4
.IX Item "-no_resumption_on_reneg"
set \s-1SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION\s0 flag.
.IP "\fB\-status\fR" 4
.IX Item "-status"
enables certificate status request support (aka \s-1OCSP\s0 stapling).
.IP "\fB\-status_verbose\fR" 4
.IX Item "-status_verbose"
enables certificate status request support (aka \s-1OCSP\s0 stapling) and gives
a verbose printout of the \s-1OCSP\s0 response.
.IP "\fB\-status_timeout nsec\fR" 4
.IX Item "-status_timeout nsec"
sets the timeout for \s-1OCSP\s0 response to \fBnsec\fR seconds.
.IP "\fB\-status_url url\fR" 4
.IX Item "-status_url url"
sets a fallback responder \s-1URL\s0 to use if no responder \s-1URL\s0 is present in the
server certificate. Without this option an error is returned if the server
certificate does not contain a responder address.
.IP "\fB\-alpn protocols\fR, \fB\-nextprotoneg protocols\fR" 4
.IX Item "-alpn protocols, -nextprotoneg protocols"
these flags enable the 
Enable the Application-Layer Protocol Negotiation or Next Protocol
Negotiation extension, respectively. \s-1ALPN\s0 is the \s-1IETF\s0 standard and
replaces \s-1NPN.\s0
The \fBprotocols\fR list is a
comma-separated list of supported protocol names.
The list should contain most wanted protocols first.
Protocol names are printable \s-1ASCII\s0 strings, for example \*(L"http/1.1\*(R" or
\&\*(L"spdy/3\*(R".
.SH "CONNECTED COMMANDS"
.IX Header "CONNECTED COMMANDS"
If a connection request is established with an \s-1SSL\s0 client and neither the
\&\fB\-www\fR nor the \fB\-WWW\fR option has been used then normally any data received
from the client is displayed and any key presses will be sent to the client.
.PP
Certain single letter commands are also recognized which perform special
operations: these are listed below.
.IP "\fBq\fR" 4
.IX Item "q"
end the current \s-1SSL\s0 connection but still accept new connections.
.IP "\fBQ\fR" 4
.IX Item "Q"
end the current \s-1SSL\s0 connection and exit.
.IP "\fBr\fR" 4
.IX Item "r"
renegotiate the \s-1SSL\s0 session.
.IP "\fBR\fR" 4
.IX Item "R"
renegotiate the \s-1SSL\s0 session and request a client certificate.
.IP "\fBP\fR" 4
.IX Item "P"
send some plain text down the underlying \s-1TCP\s0 connection: this should
cause the client to disconnect due to a protocol violation.
.IP "\fBS\fR" 4
.IX Item "S"
print out some session cache status information.
.SH "NOTES"
.IX Header "NOTES"
\&\fBs_server\fR can be used to debug \s-1SSL\s0 clients. To accept connections from
a web browser the command:
.PP
.Vb 1
\& openssl s_server \-accept 443 \-www
.Ve
.PP
can be used for example.
.PP
Most web browsers (in particular Netscape and \s-1MSIE\s0) only support \s-1RSA\s0 cipher
suites, so they cannot connect to servers which don't use a certificate
carrying an \s-1RSA\s0 key or a version of OpenSSL with \s-1RSA\s0 disabled.
.PP
Although specifying an empty list of CAs when requesting a client certificate
is strictly speaking a protocol violation, some \s-1SSL\s0 clients interpret this to
mean any \s-1CA\s0 is acceptable. This is useful for debugging purposes.
.PP
The session parameters can printed out using the \fBsess_id\fR program.
.SH "BUGS"
.IX Header "BUGS"
Because this program has a lot of options and also because some of
the techniques used are rather old, the C source of s_server is rather
hard to read and not a model of how things should be done. A typical
\&\s-1SSL\s0 server program would be much simpler.
.PP
The output of common ciphers is wrong: it just gives the list of ciphers that
OpenSSL recognizes and the client supports.
.PP
There should be a way for the \fBs_server\fR program to print out details of any
unknown cipher suites a client says it supports.
.SH "SEE ALSO"
.IX Header "SEE ALSO"
\&\fIsess_id\fR\|(1), \fIs_client\fR\|(1), \fIciphers\fR\|(1)
.SH "HISTORY"
.IX Header "HISTORY"
The \-no_alt_chains options was first added to OpenSSL 1.0.2b.
OpenPOWER on IntegriCloud