2 {- OpenSSL::safe::output_do_not_edit_headers(); -}
6 openssl-s_server - SSL/TLS server program
10 B<openssl> B<s_server>
23 [B<-certform> B<DER>|B<PEM>|B<P12>]
24 [B<-cert_chain> I<infile>]
26 [B<-serverinfo> I<val>]
29 [B<-keyform> B<DER>|B<PEM>|B<P12>|B<ENGINE>]
32 [B<-dcertform> B<DER>|B<PEM>|B<P12>]
33 [B<-dcert_chain> I<infile>]
35 [B<-dkeyform> B<DER>|B<PEM>|B<P12>|B<ENGINE>]
41 [B<-msgfile> I<outfile>]
45 [B<-no_resume_ephemeral>]
48 [B<-http_server_binmode>]
51 [B<-servername_fatal>]
54 [B<-id_prefix> I<val>]
55 [B<-keymatexport> I<val>]
56 [B<-keymatexportlen> I<+int>]
58 [B<-CRLform> B<DER>|B<PEM>]
60 [B<-chainCAfile> I<infile>]
61 [B<-chainCApath> I<dir>]
62 [B<-chainCAstore> I<uri>]
63 [B<-verifyCAfile> I<infile>]
64 [B<-verifyCApath> I<dir>]
65 [B<-verifyCAstore> I<uri>]
68 [B<-verify_return_error>]
74 [B<-status_timeout> I<int>]
75 [B<-status_url> I<val>]
76 [B<-status_file> I<infile>]
79 [B<-security_debug_verbose>]
83 [B<-ssl_config> I<val>]
84 [B<-max_send_frag> I<+int>]
85 [B<-split_send_frag> I<+int>]
86 [B<-max_pipelines> I<+int>]
88 [B<-read_buf> I<+int>]
94 [B<-legacy_renegotiation>]
95 [B<-no_renegotiation>]
96 [B<-legacy_server_connect>]
97 [B<-no_resumption_on_reneg>]
98 [B<-no_legacy_server_connect>]
99 [B<-allow_no_dhe_kex>]
100 [B<-prioritize_chacha>]
103 [B<-client_sigalgs> I<val>]
106 [B<-named_curve> I<val>]
108 [B<-ciphersuites> I<val>]
109 [B<-dhparam> I<infile>]
110 [B<-record_padding> I<val>]
111 [B<-debug_broken_protocol>]
113 [B<-psk_identity> I<val>]
114 [B<-psk_hint> I<val>]
116 [B<-psk_session> I<file>]
117 [B<-srpvfile> I<infile>]
118 [B<-srpuserseed> I<val>]
125 [B<-nextprotoneg> I<val>]
126 [B<-use_srtp> I<val>]
129 [B<-keylogfile> I<outfile>]
130 [B<-recv_max_early_data> I<int>]
131 [B<-max_early_data> I<int>]
137 {- $OpenSSL::safe::opt_name_synopsis -}
138 {- $OpenSSL::safe::opt_version_synopsis -}
139 {- $OpenSSL::safe::opt_v_synopsis -}
140 {- $OpenSSL::safe::opt_s_synopsis -}
141 {- $OpenSSL::safe::opt_x_synopsis -}
142 {- $OpenSSL::safe::opt_trust_synopsis -}
143 {- $OpenSSL::safe::opt_r_synopsis -}
144 {- $OpenSSL::safe::opt_engine_synopsis -}
145 {- $OpenSSL::safe::opt_provider_synopsis -}
147 =for openssl ifdef unix 4 6 unlink no_dhe nextprotoneg use_srtp engine
149 =for openssl ifdef status status_verbose status_timeout status_url status_file
151 =for openssl ifdef psk_hint srpvfile srpuserseed sctp sctp_label_bug
153 =for openssl ifdef sctp sctp_label_bug trace mtu timeout listen
155 =for openssl ifdef ssl3 tls1 tls1_1 tls1_2 tls1_3 dtls mtu dtls1 dtls1_2
157 =for openssl ifdef sendfile
161 This command implements a generic SSL/TLS server which
162 listens for connections on a given port using SSL/TLS.
166 In addition to the options below, this command also supports
167 the common and server only options documented
168 L<SSL_CONF_cmd(3)/Supported Command Line Commands>
174 Print out a usage message.
176 =item B<-port> I<+int>
178 The TCP port to listen on for connections. If not specified 4433 is used.
180 =item B<-accept> I<val>
182 The optional TCP host and port to listen on for connections. If not specified, *:4433 is used.
184 =item B<-unix> I<val>
186 Unix domain socket to accept on.
198 For -unix, unlink any existing socket first.
200 =item B<-context> I<val>
202 Sets the SSL context id. It can be given any string value. If this option
203 is not present a default value will be used.
205 =item B<-verify> I<int>, B<-Verify> I<int>
207 The verify depth to use. This specifies the maximum length of the
208 client certificate chain and makes the server request a certificate from
209 the client. With the B<-verify> option a certificate is requested but the
210 client does not have to send one, with the B<-Verify> option the client
211 must supply a certificate or an error occurs.
213 If the cipher suite cannot request a client certificate (for example an
214 anonymous cipher suite or PSK) this option has no effect.
216 =item B<-cert> I<infile>
218 The certificate to use, most servers cipher suites require the use of a
219 certificate and some require a certificate with a certain public key type:
220 for example the DSS cipher suites require a certificate containing a DSS
221 (DSA) key. If not specified then the filename F<server.pem> will be used.
223 =item B<-certform> B<DER>|B<PEM>|B<P12>
225 The server certificate file format.
226 This option has no effect and is retained for backward compatibility only.
230 A file containing untrusted certificates to use when attempting to build the
231 certificate chain related to the certificate specified via the B<-cert> option.
233 =item B<-build_chain>
235 Specify whether the application should build the server certificate chain to be
236 provided to the client.
238 =item B<-serverinfo> I<val>
240 A file containing one or more blocks of PEM data. Each PEM block
241 must encode a TLS ServerHello extension (2 bytes type, 2 bytes length,
242 followed by "length" bytes of extension data). If the client sends
243 an empty TLS ClientHello extension matching the type, the corresponding
244 ServerHello extension will be returned.
246 =item B<-key> I<infile>
248 The private key to use. If not specified then the certificate file will
251 =item B<-keyform> B<DER>|B<PEM>|B<P12>|B<ENGINE>
253 The key format; the default is B<PEM>.
254 The only value with effect is B<ENGINE>; all others have become obsolete.
255 See L<openssl(1)/Format Options> for details.
257 =item B<-pass> I<val>
259 The private key password source.
260 For more information about the format of I<val>,
261 see L<openssl(1)/Pass Phrase Options>.
263 =item B<-dcert> I<infile>, B<-dkey> I<infile>
265 Specify an additional certificate and private key, these behave in the
266 same manner as the B<-cert> and B<-key> options except there is no default
267 if they are not specified (no additional certificate and key is used). As
268 noted above some cipher suites require a certificate containing a key of
269 a certain type. Some cipher suites need a certificate carrying an RSA key
270 and some a DSS (DSA) key. By using RSA and DSS certificates and keys
271 a server can support clients which only support RSA or DSS cipher suites
272 by using an appropriate certificate.
274 =item B<-dcert_chain>
276 A file containing untrusted certificates to use when attempting to build the
277 server certificate chain when a certificate specified via the B<-dcert> option
280 =item B<-dcertform> B<DER>|B<PEM>|B<P12>
282 The format of the additional certificate file.
283 This option has no effect and is retained for backward compatibility only.
285 =item B<-dkeyform> B<DER>|B<PEM>|B<P12>|B<ENGINE>
287 The format of the additional private key; the default is B<PEM>.
288 The only value with effect is B<ENGINE>; all others have become obsolete.
289 See L<openssl(1)/Format Options>.
291 =item B<-dpass> I<val>
293 The passphrase for the additional private key.
294 For more information about the format of I<val>,
295 see L<openssl(1)/Pass Phrase Options>.
299 Tests non blocking I/O.
303 This option translated a line feed from the terminal into CR+LF.
307 Print extensive debugging information including a hex dump of all traffic.
311 Show all protocol messages with hex dump.
313 =item B<-msgfile> I<outfile>
315 File to send output of B<-msg> or B<-trace> to, default standard output.
319 Prints the SSL session states.
321 =item B<-CRL> I<infile>
325 =item B<-CRLform> B<DER>|B<PEM>
327 The CRL file format; the default is B<PEM>.
328 See L<openssl(1)/Format Options> for details.
330 =item B<-crl_download>
332 Download CRLs from distribution points given in CDP extensions of certificates
334 =item B<-verifyCAfile> I<filename>
336 A file in PEM format CA containing trusted certificates to use
337 for verifying client certificates.
339 =item B<-verifyCApath> I<dir>
341 A directory containing trusted certificates to use
342 for verifying client certificates.
343 This directory must be in "hash format",
344 see L<openssl-verify(1)> for more information.
346 =item B<-verifyCAstore> I<uri>
348 The URI of a store containing trusted certificates to use
349 for verifying client certificates.
351 =item B<-chainCAfile> I<file>
353 A file in PEM format containing trusted certificates to use
354 when attempting to build the server certificate chain.
356 =item B<-chainCApath> I<dir>
358 A directory containing trusted certificates to use
359 for building the server certificate chain provided to the client.
360 This directory must be in "hash format",
361 see L<openssl-verify(1)> for more information.
363 =item B<-chainCAstore> I<uri>
365 The URI of a store containing trusted certificates to use
366 for building the server certificate chain provided to the client.
367 The URI may indicate a single certificate, as well as a collection of them.
368 With URIs in the C<file:> scheme, this acts as B<-chainCAfile> or
369 B<-chainCApath>, depending on if the URI indicates a directory or a
371 See L<ossl_store-file(7)> for more information on the C<file:> scheme.
375 If this option is set then no certificate is used. This restricts the
376 cipher suites available to the anonymous ones (currently just anonymous
381 Inhibit printing of session and certificate information.
383 =item B<-tlsextdebug>
385 Print a hex dump of any TLS extensions received from the server.
389 Sends a status message back to the client when it connects. This includes
390 information about the ciphers used and various session parameters.
391 The output is in HTML format so this option can be used with a web browser.
392 The special URL C</renegcert> turns on client cert validation, and C</reneg>
393 tells the server to request renegotiation.
394 The B<-early_data> option cannot be used with this option.
396 =item B<-WWW>, B<-HTTP>
398 Emulates a simple web server. Pages will be resolved relative to the
399 current directory, for example if the URL C<https://myhost/page.html> is
400 requested the file F<./page.html> will be sent.
401 If the B<-HTTP> flag is used, the files are sent directly, and should contain
402 any HTTP response headers (including status response line).
403 If the B<-WWW> option is used,
404 the response headers are generated by the server, and the file extension is
405 examined to determine the B<Content-Type> header.
406 Extensions of C<html>, C<htm>, and C<php> are C<text/html> and all others are
408 In addition, the special URL C</stats> will return status
409 information like the B<-www> option.
410 Neither of these options can be used in conjunction with B<-early_data>.
412 =item B<-http_server_binmode>
414 When acting as web-server (using option B<-WWW> or B<-HTTP>) open files requested
415 by the client in binary mode.
417 =item B<-no_ca_names>
419 Disable TLS Extension CA Names. You may want to disable it for security reasons
420 or for compatibility with some Windows TLS implementations crashing when this
421 extension is larger than 1024 bytes.
423 =item B<-id_prefix> I<val>
425 Generate SSL/TLS session IDs prefixed by I<val>. This is mostly useful
426 for testing any SSL/TLS code (eg. proxies) that wish to deal with multiple
427 servers, when each of which might be generating a unique range of session
428 IDs (eg. with a certain prefix).
430 =item B<-verify_return_error>
432 Verification errors normally just print a message but allow the
433 connection to continue, for debugging purposes.
434 If this option is used, then verification errors close the connection.
438 Enables certificate status request support (aka OCSP stapling).
440 =item B<-status_verbose>
442 Enables certificate status request support (aka OCSP stapling) and gives
443 a verbose printout of the OCSP response.
445 =item B<-status_timeout> I<int>
447 Sets the timeout for OCSP response to I<int> seconds.
449 =item B<-status_url> I<val>
451 Sets a fallback responder URL to use if no responder URL is present in the
452 server certificate. Without this option an error is returned if the server
453 certificate does not contain a responder address.
455 =item B<-status_file> I<infile>
457 Overrides any OCSP responder URLs from the certificate and always provides the
458 OCSP Response stored in the file. The file must be in DER format.
462 Show verbose trace output of protocol messages. OpenSSL needs to be compiled
463 with B<enable-ssl-trace> for this option to work.
467 Provide a brief summary of connection parameters instead of the normal verbose
472 Simple test server which just reverses the text received from the client
473 and sends it back to the server. Also sets B<-brief>. Cannot be used in
474 conjunction with B<-early_data>.
478 Switch on asynchronous mode. Cryptographic operations will be performed
479 asynchronously. This will only have an effect if an asynchronous capable engine
480 is also used via the B<-engine> option. For test purposes the dummy async engine
481 (dasync) can be used (if available).
483 =item B<-max_send_frag> I<+int>
485 The maximum size of data fragment to send.
486 See L<SSL_CTX_set_max_send_fragment(3)> for further information.
488 =item B<-split_send_frag> I<+int>
490 The size used to split data for encrypt pipelines. If more data is written in
491 one go than this value then it will be split into multiple pipelines, up to the
492 maximum number of pipelines defined by max_pipelines. This only has an effect if
493 a suitable cipher suite has been negotiated, an engine that supports pipelining
494 has been loaded, and max_pipelines is greater than 1. See
495 L<SSL_CTX_set_split_send_fragment(3)> for further information.
497 =item B<-max_pipelines> I<+int>
499 The maximum number of encrypt/decrypt pipelines to be used. This will only have
500 an effect if an engine has been loaded that supports pipelining (e.g. the dasync
501 engine) and a suitable cipher suite has been negotiated. The default value is 1.
502 See L<SSL_CTX_set_max_pipelines(3)> for further information.
504 =item B<-naccept> I<+int>
506 The server will exit after receiving the specified number of connections,
509 =item B<-read_buf> I<+int>
511 The default read buffer size to be used for connections. This will only have an
512 effect if the buffer size is larger than the size that would otherwise be used
513 and pipelining is in use (see L<SSL_CTX_set_default_read_buffer_len(3)> for
514 further information).
518 There are several known bugs in SSL and TLS implementations. Adding this
519 option enables various workarounds.
523 Disable negotiation of TLS compression.
524 TLS compression is not recommended and is off by default as of
529 Enable negotiation of TLS compression.
530 This option was introduced in OpenSSL 1.1.0.
531 TLS compression is not recommended and is off by default as of
536 Disable RFC4507bis session ticket support. This option has no effect if TLSv1.3
537 is negotiated. See B<-num_tickets>.
539 =item B<-num_tickets>
541 Control the number of tickets that will be sent to the client after a full
542 handshake in TLSv1.3. The default number of tickets is 2. This option does not
543 affect the number of tickets sent after a resumption handshake.
547 Use the server's cipher preferences, rather than the client's preferences.
549 =item B<-prioritize_chacha>
551 Prioritize ChaCha ciphers when preferred by clients. Requires B<-serverpref>.
553 =item B<-no_resumption_on_reneg>
555 Set the B<SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION> option.
557 =item B<-client_sigalgs> I<val>
559 Signature algorithms to support for client certificate authentication
560 (colon-separated list).
562 =item B<-named_curve> I<val>
564 Specifies the elliptic curve to use. NOTE: this is single curve, not a list.
565 For a list of all possible curves, use:
567 $ openssl ecparam -list_curves
569 =item B<-cipher> I<val>
571 This allows the list of TLSv1.2 and below ciphersuites used by the server to be
572 modified. This list is combined with any TLSv1.3 ciphersuites that have been
573 configured. When the client sends a list of supported ciphers the first client
574 cipher also included in the server list is used. Because the client specifies
575 the preference order, the order of the server cipherlist is irrelevant. See
576 L<openssl-ciphers(1)> for more information.
578 =item B<-ciphersuites> I<val>
580 This allows the list of TLSv1.3 ciphersuites used by the server to be modified.
581 This list is combined with any TLSv1.2 and below ciphersuites that have been
582 configured. When the client sends a list of supported ciphers the first client
583 cipher also included in the server list is used. Because the client specifies
584 the preference order, the order of the server cipherlist is irrelevant. See
585 L<openssl-ciphers(1)> command for more information. The format for this list is
586 a simple colon (":") separated list of TLSv1.3 ciphersuite names.
588 =item B<-dhparam> I<infile>
590 The DH parameter file to use. The ephemeral DH cipher suites generate keys
591 using a set of DH parameters. If not specified then an attempt is made to
592 load the parameters from the server certificate file.
593 If this fails then a static set of parameters hard coded into this command
598 Turns on non blocking I/O.
600 =item B<-psk_identity> I<val>
602 Expect the client to send PSK identity I<val> when using a PSK
603 cipher suite, and warn if they do not. By default, the expected PSK
604 identity is the string "Client_identity".
606 =item B<-psk_hint> I<val>
608 Use the PSK identity hint I<val> when using a PSK cipher suite.
612 Use the PSK key I<val> when using a PSK cipher suite. The key is
613 given as a hexadecimal number without leading 0x, for example -psk
615 This option must be provided in order to use a PSK cipher.
617 =item B<-psk_session> I<file>
619 Use the pem encoded SSL_SESSION data stored in I<file> as the basis of a PSK.
620 Note that this will only work if TLSv1.3 is negotiated.
624 This option can only be used in conjunction with one of the DTLS options above.
625 With this option, this command will listen on a UDP port for incoming
627 Any ClientHellos that arrive will be checked to see if they have a cookie in
629 Any without a cookie will be responded to with a HelloVerifyRequest.
630 If a ClientHello with a cookie is received then this command will
631 connect to that peer and complete the handshake.
635 Use SCTP for the transport protocol instead of UDP in DTLS. Must be used in
636 conjunction with B<-dtls>, B<-dtls1> or B<-dtls1_2>. This option is only
637 available where OpenSSL has support for SCTP enabled.
639 =item B<-sctp_label_bug>
641 Use the incorrect behaviour of older OpenSSL implementations when computing
642 endpoint-pair shared secrets for DTLS/SCTP. This allows communication with
643 older broken implementations but breaks interoperability with correct
644 implementations. Must be used in conjunction with B<-sctp>. This option is only
645 available where OpenSSL has support for SCTP enabled.
649 If this option is set then no DH parameters will be loaded effectively
650 disabling the ephemeral DH cipher suites.
652 =item B<-alpn> I<val>, B<-nextprotoneg> I<val>
654 These flags enable the Enable the Application-Layer Protocol Negotiation
655 or Next Protocol Negotiation (NPN) extension, respectively. ALPN is the
656 IETF standard and replaces NPN.
657 The I<val> list is a comma-separated list of supported protocol
658 names. The list should contain the most desirable protocols first.
659 Protocol names are printable ASCII strings, for example "http/1.1" or
661 The flag B<-nextprotoneg> cannot be specified if B<-tls1_3> is used.
665 If this option is set and KTLS is enabled, SSL_sendfile() will be used
666 instead of BIO_write() to send the HTTP response requested by a client.
667 This option is only valid if B<-WWW> or B<-HTTP> is specified.
669 =item B<-keylogfile> I<outfile>
671 Appends TLS secrets to the specified keylog file such that external programs
672 (like Wireshark) can decrypt TLS connections.
674 =item B<-max_early_data> I<int>
676 Change the default maximum early data bytes that are specified for new sessions
677 and any incoming early data (when used in conjunction with the B<-early_data>
678 flag). The default value is approximately 16k. The argument must be an integer
679 greater than or equal to 0.
681 =item B<-recv_max_early_data> I<int>
683 Specify the hard limit on the maximum number of early data bytes that will
688 Accept early data where possible. Cannot be used in conjunction with B<-www>,
689 B<-WWW>, B<-HTTP> or B<-rev>.
693 Require TLSv1.3 cookies.
695 =item B<-anti_replay>, B<-no_anti_replay>
697 Switches replay protection on or off, respectively. Replay protection is on by
698 default unless overridden by a configuration file. When it is on, OpenSSL will
699 automatically detect if a session ticket has been used more than once, TLSv1.3
700 has been negotiated, and early data is enabled on the server. A full handshake
701 is forced if a session ticket is used a second or subsequent time. Any early
702 data that was sent will be rejected.
704 {- $OpenSSL::safe::opt_name_item -}
706 {- $OpenSSL::safe::opt_version_item -}
708 {- $OpenSSL::safe::opt_s_item -}
710 {- $OpenSSL::safe::opt_x_item -}
712 {- $OpenSSL::safe::opt_trust_item -}
714 {- $OpenSSL::safe::opt_r_item -}
716 {- $OpenSSL::safe::opt_engine_item -}
718 {- $OpenSSL::safe::opt_provider_item -}
720 {- $OpenSSL::safe::opt_v_item -}
722 If the server requests a client certificate, then
723 verification errors are displayed, for debugging, but the command will
724 proceed unless the B<-verify_return_error> option is used.
728 =head1 CONNECTED COMMANDS
730 If a connection request is established with an SSL client and neither the
731 B<-www> nor the B<-WWW> option has been used then normally any data received
732 from the client is displayed and any key presses will be sent to the client.
734 Certain commands are also recognized which perform special operations. These
735 commands are a letter which must appear at the start of a line. They are listed
742 End the current SSL connection but still accept new connections.
746 End the current SSL connection and exit.
750 Renegotiate the SSL session (TLSv1.2 and below only).
754 Renegotiate the SSL session and request a client certificate (TLSv1.2 and below
759 Send some plain text down the underlying TCP connection: this should
760 cause the client to disconnect due to a protocol violation.
764 Print out some session cache status information.
768 Send a key update message to the client (TLSv1.3 only)
772 Send a key update message to the client and request one back (TLSv1.3 only)
776 Send a certificate request to the client (TLSv1.3 only)
782 This command can be used to debug SSL clients. To accept connections
783 from a web browser the command:
785 openssl s_server -accept 443 -www
787 can be used for example.
789 Although specifying an empty list of CAs when requesting a client certificate
790 is strictly speaking a protocol violation, some SSL clients interpret this to
791 mean any CA is acceptable. This is useful for debugging purposes.
793 The session parameters can printed out using the L<openssl-sess_id(1)> command.
797 Because this program has a lot of options and also because some of the
798 techniques used are rather old, the C source for this command is rather
799 hard to read and not a model of how things should be done.
800 A typical SSL server program would be much simpler.
802 The output of common ciphers is wrong: it just gives the list of ciphers that
803 OpenSSL recognizes and the client supports.
805 There should be a way for this command to print out details
806 of any unknown cipher suites a client says it supports.
811 L<openssl-sess_id(1)>,
812 L<openssl-s_client(1)>,
813 L<openssl-ciphers(1)>,
815 L<SSL_CTX_set_max_send_fragment(3)>,
816 L<SSL_CTX_set_split_send_fragment(3)>,
817 L<SSL_CTX_set_max_pipelines(3)>,
818 L<ossl_store-file(7)>
822 The -no_alt_chains option was added in OpenSSL 1.1.0.
825 -allow-no-dhe-kex and -prioritize_chacha options were added in OpenSSL 1.1.1.
827 All B<-keyform> and B<-dkeyform> values except B<ENGINE>
828 have become obsolete in OpenSSL 3.0.0 and have no effect.
830 The B<-certform> and B<-dcertform> options have become obsolete in OpenSSL 3.0.0
835 Copyright 2000-2020 The OpenSSL Project Authors. All Rights Reserved.
837 Licensed under the Apache License 2.0 (the "License"). You may not use
838 this file except in compliance with the License. You can obtain a copy
839 in the file LICENSE in the source distribution or at
840 L<https://www.openssl.org/source/license.html>.