Update documentation of SSL METHODs and ciphers
Reviewed-by: Kurt Roeckx <kurt@openssl.org>
diff --git a/doc/apps/ciphers.pod b/doc/apps/ciphers.pod
index 02fc57a..07c353d 100644
--- a/doc/apps/ciphers.pod
+++ b/doc/apps/ciphers.pod
@@ -32,7 +32,7 @@
=item B<-help>
-Print out a usage message.
+Print a usage message.
=item B<-s>
@@ -53,21 +53,25 @@
Like B<-v>, but include the official cipher suite values in hex.
+=item B<-tls1_2>
+
+In combination with the B<-s> option, list the ciphers which would be used if
+TLSv1.2 were negotiated.
+
=item B<-ssl3>
-List the ciphers which would be used if SSL v3 was negotiated.
+In combination with the B<-s> option, list the ciphers which would be used if
+SSLv3 were negotiated.
=item B<-tls1>
-List the ciphers which would be used if TLS v1.0 was negotiated.
+In combination with the B<-s> option, list the ciphers which would be used if
+TLSv1 were negotiated.
=item B<-tls1_1>
-List the ciphers which would be used if TLS v1.1 was negotiated.
-
-=item B<-tls1_2>
-
-List the ciphers which would be used if TLS v1.2 was negotiated.
+In combination with the B<-s> option, list the ciphers which would be used if
+TLSv1.1 were negotiated.
=item B<-stdname>
@@ -132,25 +136,27 @@
=item B<DEFAULT>
-the default cipher list. This is determined at compile time and
-is B<ALL:!COMPLEMENTOFDEFAULT:!eNULL>. This must be the first cipher
-string specified.
+The default cipher list.
+This is determined at compile time and is normally
+B<ALL:!COMPLEMENTOFDEFAULT:!eNULL>.
+When used, this must be the first cipherstring specified.
=item B<COMPLEMENTOFDEFAULT>
-the ciphers included in B<ALL>, but not enabled by default. Currently
+The ciphers included in B<ALL>, but not enabled by default. Currently
this includes all RC4, DES, RC2 and anonymous ciphers. Note that this rule does
not cover B<eNULL>, which is not included by B<ALL> (use B<COMPLEMENTOFALL> if
necessary).
=item B<ALL>
-all cipher suites except the B<eNULL> ciphers which must be explicitly enabled;
-as of OpenSSL, the B<ALL> cipher suites are reasonably ordered by default
+All cipher suites except the B<eNULL> ciphers (which must be explicitly enabled
+if needed).
+As of OpenSSL 1.0.0, the B<ALL> cipher suites are sensibly ordered by default.
=item B<COMPLEMENTOFALL>
-the cipher suites not enabled by B<ALL>, currently being B<eNULL>.
+The cipher suites not enabled by B<ALL>, currently B<eNULL>.
=item B<HIGH>
@@ -170,83 +176,86 @@
=item B<eNULL>, B<NULL>
-the "NULL" ciphers that is those offering no encryption. Because these offer no
-encryption at all and are a security risk they are disabled unless explicitly
-included.
+The "NULL" ciphers that is those offering no encryption. Because these offer no
+encryption at all and are a security risk they are not enabled via either the
+B<DEFAULT> or B<ALL> cipher strings.
+Be careful when building cipherlists out of lower-level primitives such as
+B<kRSA> or B<aECDSA> as these do overlap with the B<eNULL> ciphers. When in
+doubt, include B<!eNULL> in your cipherlist.
=item B<aNULL>
-the cipher suites offering no authentication. This is currently the anonymous
+The cipher suites offering no authentication. This is currently the anonymous
DH algorithms and anonymous ECDH algorithms. These cipher suites are vulnerable
-to a "man in the middle" attack and so their use is normally discouraged.
+to "man in the middle" attacks and so their use is discouraged.
+These are excluded from the B<DEFAULT> ciphers, but included in the B<ALL>
+ciphers.
+Be careful when building cipherlists out of lower-level primitives such as
+B<kDHE> or B<AES> as these do overlap with the B<aNULL> ciphers.
+When in doubt, include B<!aNULL> in your cipherlist.
=item B<kRSA>, B<aRSA>, B<RSA>
-cipher suites using RSA key exchange, authentication or either respectively.
+Cipher suites using RSA key exchange, authentication or either respectively.
=item B<kDHr>, B<kDHd>, B<kDH>
-cipher suites using DH key agreement and DH certificates signed by CAs with RSA
-and DSS keys or either respectively.
+Cipher suites using static DH key agreement and DH certificates signed by CAs
+with RSA and DSS keys or either respectively.
+All these cipher suites have been removed in OpenSSL 1.1.0.
-=item B<kDHE>, B<kEDH>
+=item B<kDHE>, B<kEDH>, B<DH>
-cipher suites using ephemeral DH key agreement, including anonymous cipher
+Cipher suites using ephemeral DH key agreement, including anonymous cipher
suites.
=item B<DHE>, B<EDH>
-cipher suites using authenticated ephemeral DH key agreement.
+Cipher suites using authenticated ephemeral DH key agreement.
=item B<ADH>
-anonymous DH cipher suites, note that this does not include anonymous Elliptic
+Anonymous DH cipher suites, note that this does not include anonymous Elliptic
Curve DH (ECDH) cipher suites.
-=item B<DH>
+=item B<kEECDH>, B<kECDHE>, B<ECDH>
-cipher suites using DH, including anonymous DH, ephemeral DH and fixed DH.
-
-=item B<kEECDH>, B<kECDHE>
-
-cipher suites using ephemeral ECDH key agreement, including anonymous
+Cipher suites using ephemeral ECDH key agreement, including anonymous
cipher suites.
=item B<ECDHE>, B<EECDH>
-cipher suites using authenticated ephemeral ECDH key agreement.
+Cipher suites using authenticated ephemeral ECDH key agreement.
=item B<AECDH>
-anonymous Elliptic Curve Diffie Hellman cipher suites.
-
-=item B<ECDH>
-
-cipher suites using ECDH key exchange, including anonymous and ephemeral.
+Anonymous Elliptic Curve Diffie Hellman cipher suites.
=item B<aDSS>, B<DSS>
-cipher suites using DSS authentication, i.e. the certificates carry DSS keys.
+Cipher suites using DSS authentication, i.e. the certificates carry DSS keys.
=item B<aDH>
-cipher suites effectively using DH authentication, i.e. the certificates carry
+Cipher suites effectively using DH authentication, i.e. the certificates carry
DH keys.
+All these cipher suites have been removed in OpenSSL 1.1.0.
=item B<aECDSA>, B<ECDSA>
-cipher suites using ECDSA authentication, i.e. the certificates carry ECDSA
+Cipher suites using ECDSA authentication, i.e. the certificates carry ECDSA
keys.
=item B<TLSv1.2>, B<TLSv1.0>, B<SSLv3>
-Lists ciphersuites which are only supported in at least TLS v1.2, TLS v1.0
-or SSL v3.0 respectively. Note: there are no ciphersuites specific to TLS v1.1.
-Since this is only the minimum version if, for example, TLS v1.0 is supported
-then both TLS v1.0 and SSL v3.0 ciphersuites are included.
+Lists ciphersuites which are only supported in at least TLS v1.2, TLS v1.0 or
+SSL v3.0 respectively.
+Note: there are no ciphersuites specific to TLS v1.1.
+Since this is only the minimum version, if, for example, TLSv1.0 is negotiated
+then both TLSv1.0 and SSLv3.0 ciphersuites are available.
Note: these cipher strings B<do not> change the negotiated version of SSL or
-TLS only the list of cipher suites.
+TLS, they only affect the list of available cipher suites.
=item B<AES128>, B<AES256>, B<AES>
@@ -279,81 +288,85 @@
=item B<DES>
-cipher suites using DES (not triple DES).
+Cipher suites using DES (not triple DES).
+All these cipher suites have been removed in OpenSSL 1.1.0.
=item B<RC4>
-cipher suites using RC4.
+Cipher suites using RC4.
=item B<RC2>
-cipher suites using RC2.
+Cipher suites using RC2.
=item B<IDEA>
-cipher suites using IDEA.
+Cipher suites using IDEA.
=item B<SEED>
-cipher suites using SEED.
+Cipher suites using SEED.
=item B<MD5>
-cipher suites using MD5.
+Cipher suites using MD5.
=item B<SHA1>, B<SHA>
-cipher suites using SHA1.
+Cipher suites using SHA1.
=item B<SHA256>, B<SHA384>
-ciphersuites using SHA256 or SHA384.
+Ciphersuites using SHA256 or SHA384.
-=item B<aGOST>
+=item B<aGOST>
-cipher suites using GOST R 34.10 (either 2001 or 94) for authentication
-(needs an engine supporting GOST algorithms).
+Cipher suites using GOST R 34.10 (either 2001 or 94) for authentication
+(needs an engine supporting GOST algorithms).
=item B<aGOST01>
-cipher suites using GOST R 34.10-2001 authentication.
+Cipher suites using GOST R 34.10-2001 authentication.
=item B<kGOST>
-cipher suites, using VKO 34.10 key exchange, specified in the RFC 4357.
+Cipher suites, using VKO 34.10 key exchange, specified in the RFC 4357.
=item B<GOST94>
-cipher suites, using HMAC based on GOST R 34.11-94.
+Cipher suites, using HMAC based on GOST R 34.11-94.
=item B<GOST89MAC>
-cipher suites using GOST 28147-89 MAC B<instead of> HMAC.
+Cipher suites using GOST 28147-89 MAC B<instead of> HMAC.
=item B<PSK>
-all cipher suites using pre-shared keys (PSK).
+All cipher suites using pre-shared keys (PSK).
=item B<kPSK>, B<kECDHEPSK>, B<kDHEPSK>, B<kRSAPSK>
-cipher suites using PSK key exchange, ECDHE_PSK, DHE_PSK or RSA_PSK.
+Cipher suites using PSK key exchange, ECDHE_PSK, DHE_PSK or RSA_PSK.
=item B<aPSK>
-cipher suites using PSK authentication (currently all PSK modes apart from
+Cipher suites using PSK authentication (currently all PSK modes apart from
RSA_PSK).
=item B<SUITEB128>, B<SUITEB128ONLY>, B<SUITEB192>
-enables suite B mode operation using 128 (permitting 192 bit mode by peer)
+Enables suite B mode of operation using 128 (permitting 192 bit mode by peer)
128 bit (not permitting 192 bit by peer) or 192 bit level of security
-respectively. If used these cipherstrings should appear first in the cipher
-list and anything after them is ignored. Setting Suite B mode has additional
-consequences required to comply with RFC6460. In particular the supported
-signature algorithms is reduced to support only ECDSA and SHA256 or SHA384,
-only the elliptic curves P-256 and P-384 can be used and only the two suite B
-compliant ciphersuites (ECDHE-ECDSA-AES128-GCM-SHA256 and
-ECDHE-ECDSA-AES256-GCM-SHA384) are permissible.
+respectively.
+If used these cipherstrings should appear first in the cipher
+list and anything after them is ignored.
+Setting Suite B mode has additional consequences required to comply with
+RFC6460.
+In particular the supported signature algorithms is reduced to support only
+ECDSA and SHA256 or SHA384, only the elliptic curves P-256 and P-384 can be
+used and only the two suite B compliant ciphersuites
+(ECDHE-ECDSA-AES128-GCM-SHA256 and ECDHE-ECDSA-AES256-GCM-SHA384) are
+permissible.
=back
@@ -473,13 +486,13 @@
TLS_ECDHE_RSA_WITH_3DES_EDE_CBC_SHA ECDHE-RSA-DES-CBC3-SHA
TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA ECDHE-RSA-AES128-SHA
TLS_ECDHE_RSA_WITH_AES_256_CBC_SHA ECDHE-RSA-AES256-SHA
-
+
TLS_ECDHE_ECDSA_WITH_NULL_SHA ECDHE-ECDSA-NULL-SHA
TLS_ECDHE_ECDSA_WITH_RC4_128_SHA ECDHE-ECDSA-RC4-SHA
TLS_ECDHE_ECDSA_WITH_3DES_EDE_CBC_SHA ECDHE-ECDSA-DES-CBC3-SHA
TLS_ECDHE_ECDSA_WITH_AES_128_CBC_SHA ECDHE-ECDSA-AES128-SHA
TLS_ECDHE_ECDSA_WITH_AES_256_CBC_SHA ECDHE-ECDSA-AES256-SHA
-
+
TLS_ECDH_anon_WITH_NULL_SHA AECDH-NULL-SHA
TLS_ECDH_anon_WITH_RC4_128_SHA AECDH-RC4-SHA
TLS_ECDH_anon_WITH_3DES_EDE_CBC_SHA AECDH-DES-CBC3-SHA
diff --git a/doc/apps/s_client.pod b/doc/apps/s_client.pod
index c5fe647..d794b34 100644
--- a/doc/apps/s_client.pod
+++ b/doc/apps/s_client.pod
@@ -64,10 +64,15 @@
[B<-quiet>]
[B<-ssl3>]
[B<-tls1>]
+[B<-tls1_1>]
+[B<-tls1_2>]
[B<-no_ssl3>]
[B<-no_tls1>]
[B<-no_tls1_1>]
[B<-no_tls1_2>]
+[B<-dtls>]
+[B<-dtls1>]
+[B<-dtls1_2>]
[B<-fallback_scsv>]
[B<-async>]
[B<-bugs>]
@@ -305,15 +310,20 @@
given as a hexadecimal number without leading 0x, for example -psk
1a2b3c4d.
-=item B<-ssl3>, B<-tls1>, B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>
+=item B<-ssl3>, B<-tls1>, B<-tls1_1>, B<-tls1_2>, B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>
-these options disable the use of certain SSL or TLS protocols. By default
-the initial handshake uses a method which should be compatible with all
-servers and permit them to use SSL v3 or TLS as appropriate.
+These options require or disable the use of the specified SSL or TLS protocols.
+By default B<s_client> will negotiate the highest mutually supported protocol
+version.
+When a specific TLS version is required, only that version will be offered to
+and accepted from the server.
-Unfortunately there are still ancient and broken servers in use which
-cannot handle this technique and will fail to connect. Some servers only
-work if TLS is turned off.
+=item B<-dtls>, B<-dtls1>, B<-dtls1_2>
+
+These options make B<s_client> use DTLS protocols instead of TLS.
+With B<-dtls>, B<s_client> will negotiate any supported DTLS protcol version,
+whilst B<-dtls1> and B<-dtls1_2> will only support DTLS1.0 and DTLS1.2
+respectively.
=item B<-fallback_scsv>
@@ -479,10 +489,10 @@
=head1 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_client is rather
-hard to read and not a model of how things should be done. A typical
-SSL client program would be much simpler.
+Because this program has a lot of options and also because some of the
+techniques used are rather old, the C source of B<s_client> is rather hard to
+read and not a model of how things should be done.
+A typical SSL client program would be much simpler.
The B<-prexit> option is a bit of a hack. We should really report
information whenever a session is renegotiated.
diff --git a/doc/apps/s_server.pod b/doc/apps/s_server.pod
index 890a8ea..1453491 100644
--- a/doc/apps/s_server.pod
+++ b/doc/apps/s_server.pod
@@ -75,6 +75,8 @@
[B<-async>]
[B<-no_ssl3>]
[B<-no_tls1>]
+[B<-no_tls1_1>]
+[B<-no_tls1_2>]
[B<-no_dhe>]
[B<-bugs>]
[B<-comp>]
@@ -116,15 +118,15 @@
=item B<-accept port>
-the TCP port to listen on for connections. If not specified 4433 is used.
+The TCP port to listen on for connections. If not specified 4433 is used.
=item B<-naccept count>
-The server will exit after receiving B<number> connections, default unlimited.
+The server will exit after receiving B<number> connections, default unlimited.
=item B<-context id>
-sets the SSL context id. It can be given any string value. If this option
+Sets the SSL context id. It can be given any string value. If this option
is not present a default value will be used.
=item B<-cert certname>
@@ -149,12 +151,12 @@
=item B<-pass arg>
-the private key password source. For more information about the format of B<arg>
+The private key password source. For more information about the format of B<arg>
see the B<PASS PHRASE ARGUMENTS> section in L<openssl(1)>.
=item B<-dcert filename>, B<-dkey keyname>
-specify an additional certificate and private key, these behave in the
+Specify an additional certificate and private key, these behave in the
same manner as the B<-cert> and B<-key> 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
@@ -165,24 +167,25 @@
=item B<-dcertform format>, B<-dkeyform format>, B<-dpass arg>
-additional certificate and private key format and passphrase respectively.
+Additional certificate and private key format and passphrase respectively.
=item B<-nocert>
-if this option is set then no certificate is used. This restricts the
+If this option is set then no certificate is used. This restricts the
cipher suites available to the anonymous ones (currently just anonymous
DH).
=item B<-dhparam filename>
-the DH parameter file to use. The ephemeral DH cipher suites generate keys
+The DH parameter file to use. The ephemeral DH cipher suites generate keys
using a set of DH 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.
+load the parameters from the server certificate file.
+If this fails then a static set of parameters hard coded into the B<s_server>
+program will be used.
=item B<-no_dhe>
-if this option is set then no DH parameters will be loaded effectively
+If this option is set then no DH parameters will be loaded effectively
disabling the ephemeral DH cipher suites.
=item B<-crl_check>, B<-crl_check_all>
@@ -242,40 +245,40 @@
=item B<-state>
-prints out the SSL session states.
+Prints the SSL session states.
=item B<-debug>
-print extensive debugging information including a hex dump of all traffic.
+Print extensive debugging information including a hex dump of all traffic.
=item B<-msg>
-show all protocol messages with hex dump.
+Show all protocol messages with hex dump.
=item B<-trace>
-show verbose trace output of protocol messages. OpenSSL needs to be compiled
+Show verbose trace output of protocol messages. OpenSSL needs to be compiled
with B<enable-ssl-trace> for this option to work.
=item B<-msgfile>
-file to send output of B<-msg> or B<-trace> to, default standard output.
+File to send output of B<-msg> or B<-trace> to, default standard output.
=item B<-nbio_test>
-tests non blocking I/O
+Tests non blocking I/O
=item B<-nbio>
-turns on non blocking I/O
+Turns on non blocking I/O
=item B<-crlf>
-this option translated a line feed from the terminal into CR+LF.
+This option translated a line feed from the terminal into CR+LF.
=item B<-quiet>
-inhibit printing of session and certificate information.
+Inhibit printing of session and certificate information.
=item B<-psk_hint hint>
@@ -287,37 +290,41 @@
given as a hexadecimal number without leading 0x, for example -psk
1a2b3c4d.
-=item B<-ssl3>, B<-tls1>, B<-no_ssl3>, B<-no_tls1>
+=item B<-ssl2>, B<-ssl3>, B<-tls1>, B<-tls1_1>, B<-tls1_2>, B<-no_ssl2>, B<-no_ssl3>, B<-no_tls1>, B<-no_tls1_1>, B<-no_tls1_2>
-these options disable the use of certain SSL or TLS protocols. By default
-the initial handshake uses a method which should be compatible with all
-servers and permit them to use SSL v3 or TLS as appropriate.
+These options require or disable the use of the specified SSL or TLS protocols.
+By default B<s_server> will negotiate the highest mutually supported protocol
+version.
+When a specific TLS version is required, only that version will be accepted
+from the client.
=item B<-dtls>, B<-dtls1>, B<-dtls1_2>
-these options make s_server use DTLS protocols instead of TLS. With B<-dtls>
-s_server will negotiate any supported DTLS protcol version, whilst B<-dtls1> and
-B<-dtls1_2> will only support DTLS1.0 and DTLS1.2 respectively.
+These options make B<s_server> use DTLS protocols instead of TLS.
+With B<-dtls>, B<s_server> will negotiate any supported DTLS protcol version,
+whilst B<-dtls1> and B<-dtls1_2> will only support DTLSv1.0 and DTLSv1.2
+respectively.
=item B<-listen>
-this option can only be used in conjunction with one of the DTLS options above.
-With this option s_server will listen on a UDP port for incoming connections.
+This option can only be used in conjunction with one of the DTLS options above.
+With this option B<s_server> will listen on a UDP port for incoming connections.
Any ClientHellos that arrive will be checked to see if they have a cookie in
-them or not. Any without a cookie will be responded to with a
-HelloVerifyRequest. If a ClientHello with a cookie is received then s_server
-will connect to that peer and complete the handshake.
+them or not.
+Any without a cookie will be responded to with a HelloVerifyRequest.
+If a ClientHello with a cookie is received then B<s_server> will connect to
+that peer and complete the handshake.
=item B<-async>
-switch on asynchronous mode. Cryptographic operations will be performed
+Switch on asynchronous mode. Cryptographic operations will be performed
asynchronously. This will only have an effect if an asynchronous capable engine
is also used via the B<-engine> option. For test purposes the dummy async engine
(dasync) can be used (if available).
=item B<-bugs>
-there are several known bug in SSL and TLS implementations. Adding this
+There are several known bug in SSL and TLS implementations. Adding this
option enables various workarounds.
=item B<-comp>
@@ -335,12 +342,12 @@
=item B<-brief>
-only provide a brief summary of connection parameters instead of the
-normal verbose output.
+Provide a brief summary of connection parameters instead of the normal verbose
+output.
=item B<-cipher cipherlist>
-this allows the cipher list used by the server to be modified. When
+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
@@ -348,32 +355,32 @@
=item B<-serverpref>
-use the server's cipher preferences, rather than the client's preferences.
+Use the server's cipher preferences, rather than the client's preferences.
=item B<-tlsextdebug>
-print out a hex dump of any TLS extensions received from the server.
+Print a hex dump of any TLS extensions received from the server.
=item B<-no_ticket>
-disable RFC4507bis session ticket support.
+Disable RFC4507bis session ticket support.
=item B<-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.
+Sends a status message back to the client when it connects. This includes
+information about the ciphers used and various session parameters.
The output is in HTML format so this option will normally be used with a
web browser.
=item B<-WWW>
-emulates a simple web server. Pages will be resolved relative to the
+Emulates a simple web server. Pages will be resolved relative to the
current directory, for example if the URL https://myhost/page.html is
requested the file ./page.html will be loaded.
=item B<-HTTP>
-emulates a simple web server. Pages will be resolved relative to the
+Emulates a simple web server. Pages will be resolved relative to the
current directory, for example if the URL https://myhost/page.html is
requested the file ./page.html will be loaded. The files loaded are
assumed to contain a complete and correct HTTP response (lines that
@@ -381,26 +388,26 @@
=item B<-rev>
-simple test server which just reverses the text received from the client
+Simple test server which just reverses the text received from the client
and sends it back to the server. Also sets B<-brief>.
=item B<-engine id>
-specifying an engine (by its unique B<id> string) will cause B<s_server>
+Specifying an engine (by its unique B<id> string) will cause B<s_server>
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.
=item B<-id_prefix arg>
-generate SSL/TLS session IDs prefixed by B<arg>. This is mostly useful
+Generate SSL/TLS session IDs prefixed by B<arg>. This is mostly useful
for testing any SSL/TLS 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).
=item B<-rand file(s)>
-a file or files containing random data used to seed the random number
+A file or files containing random data used to seed the random number
generator, or an EGD socket (see L<RAND_egd(3)>).
Multiple files can be specified separated by a OS-dependent character.
The separator is B<;> for MS-Windows, B<,> for OpenVMS, and B<:> for
@@ -408,7 +415,7 @@
=item B<-serverinfo file>
-a file containing one or more blocks of PEM data. Each PEM block
+A file containing one or more blocks of PEM data. Each PEM block
must encode a TLS ServerHello extension (2 bytes type, 2 bytes length,
followed by "length" bytes of extension data). If the client sends
an empty TLS ClientHello extension matching the type, the corresponding
@@ -416,30 +423,30 @@
=item B<-no_resumption_on_reneg>
-set SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION flag.
+Set the B<SSL_OP_NO_SESSION_RESUMPTION_ON_RENEGOTIATION> option.
=item B<-status>
-enables certificate status request support (aka OCSP stapling).
+Enables certificate status request support (aka OCSP stapling).
=item B<-status_verbose>
-enables certificate status request support (aka OCSP stapling) and gives
+Enables certificate status request support (aka OCSP stapling) and gives
a verbose printout of the OCSP response.
=item B<-status_timeout nsec>
-sets the timeout for OCSP response to B<nsec> seconds.
+Sets the timeout for OCSP response to B<nsec> seconds.
=item B<-status_url url>
-sets a fallback responder URL to use if no responder URL is present in the
+Sets a fallback responder URL to use if no responder URL is present in the
server certificate. Without this option an error is returned if the server
certificate does not contain a responder address.
=item B<-nextprotoneg protocols>
-enable Next Protocol Negotiation TLS extension and provide a
+Enable Next Protocol Negotiation TLS extension and provide a
comma-separated list of supported protocol names.
The list should contain most wanted protocols first.
Protocol names are printable ASCII strings, for example "http/1.1" or
@@ -451,7 +458,7 @@
If a connection request is established with an SSL client and neither the
B<-www> nor the B<-WWW> option has been used then normally any data received
-from the client is displayed and any key presses will be sent to the client.
+from the client is displayed and any key presses will be sent to the client.
Certain single letter commands are also recognized which perform special
operations: these are listed below.
@@ -506,10 +513,10 @@
=head1 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
-SSL server program would be much simpler.
+Because this program has a lot of options and also because some of the
+techniques used are rather old, the C source of B<s_server> is rather hard to
+read and not a model of how things should be done.
+A typical SSL server program would be much simpler.
The output of common ciphers is wrong: it just gives the list of ciphers that
OpenSSL recognizes and the client supports.
