6 s_time - SSL/TLS performance timing program
11 [B<-connect host:port>]
15 [B<-CApath directory>]
24 [B<-cipher cipherlist>]
28 The B<s_client> command implements a generic SSL/TLS client which connects to a
29 remote host using SSL/TLS. It can request a page from the server and includes
30 the time to transfer the payload data in its timing measurements. It measures
31 the number of connections within a given timeframe, the amount of data
32 transferred (if any), and calculates the average time spent for one connection.
38 =item B<-connect host:port>
40 This specifies the host and optional port to connect to.
44 This specifies the page to GET from the server. A value of '/' gets the
45 index.htm[l] page. If this parameter is not specified, then B<s_time> will only
46 perform the handshake to establish SSL connections but not transfer any
49 =item B<-cert certname>
51 The certificate to use, if one is requested by the server. The default is
52 not to use a certificate. The file is in PEM format.
56 The private key to use. If not specified then the certificate file will
57 be used. The file is in PEM format.
59 =item B<-verify depth>
61 The verify depth to use. This specifies the maximum length of the
62 server certificate chain and turns on server certificate verification.
63 Currently the verify operation continues after errors so all the problems
64 with a certificate chain can be seen. As a side effect the connection
65 will never fail due to a server certificate verify failure.
67 =item B<-CApath directory>
69 The directory to use for server certificate verification. This directory
70 must be in "hash format", see B<verify> for more information. These are
71 also used when building the client certificate chain.
75 A file containing trusted certificates to use during server authentication
76 and to use when attempting to build the client certificate chain.
80 performs the timing test using a new session ID for each connection.
81 If neither B<-new> nor B<-reuse> are specified, they are both on by default
82 and executed in sequence.
86 performs the timing test using the same session ID; this can be used as a test
87 that session caching is working. If neither B<-new> nor B<-reuse> are
88 specified, they are both on by default and executed in sequence.
92 turns on non-blocking I/O.
96 these options disable the use of certain SSL or TLS protocols. By default
97 the initial handshake uses a method which should be compatible with all
98 servers and permit them to use SSL v3 or TLS as appropriate.
99 The timing program is not as rich in options to turn protocols on and off as
100 the L<s_client(1)|s_client(1)> program and may not connect to all servers.
102 Unfortunately there are a lot of ancient and broken servers in use which
103 cannot handle this technique and will fail to connect. Some servers only
104 work if TLS is turned off with the B<-ssl3> option.
108 there are several known bug in SSL and TLS implementations. Adding this
109 option enables various workarounds.
111 =item B<-cipher cipherlist>
113 this allows the cipher list sent by the client to be modified. Although
114 the server determines which cipher suite is used it should take the first
115 supported cipher in the list sent by the client.
116 See the L<ciphers(1)|ciphers(1)> command for more information.
118 =item B<-time length>
120 specifies how long (in seconds) B<s_time> should establish connections and
121 optionally transfer payload data from a server. Server and client performance
122 and the link speed determine how many connections B<s_time> can establish.
128 B<s_client> can be used to measure the performance of an SSL connection.
129 To connect to an SSL HTTP server and get the default page the command
131 openssl s_time -connect servername:443 -www / -CApath yourdir -CAfile yourfile.pem -cipher commoncipher [-ssl3]
133 would typically be used (https uses port 443). 'commoncipher' is a cipher to
134 which both client and server can agree, see the L<ciphers(1)|ciphers(1)> command
137 If the handshake fails then there are several possible causes, if it is
138 nothing obvious like no client certificate then the B<-bugs> and
139 B<-ssl3> options can be tried
140 in case it is a buggy server. In particular you should play with these
141 options B<before> submitting a bug report to an OpenSSL mailing list.
143 A frequent problem when attempting to get client certificates working
144 is that a web client complains it has no certificates or gives an empty
145 list to choose from. This is normally because the server is not sending
146 the clients certificate authority in its "acceptable CA list" when it
147 requests a certificate. By using L<s_client(1)|s_client(1)> the CA list can be
148 viewed and checked. However some servers only request client authentication
149 after a specific URL is requested. To obtain the list in this case it
150 is necessary to use the B<-prexit> option of L<s_client(1)|s_client(1)> and
151 send an HTTP request for an appropriate page.
153 If a certificate is specified on the command line using the B<-cert>
154 option it will not be used unless the server specifically requests
155 a client certificate. Therefor merely including a client certificate
156 on the command line is no guarantee that the certificate works.
160 Because this program does not have all the options of the
161 L<s_client(1)|s_client(1)> program to turn protocols on and off, you may not be
162 able to measure the performance of all protocols with all servers.
164 The B<-verify> option should really exit if the server verification
169 L<s_client(1)|s_client(1)>, L<s_server(1)|s_server(1)>, L<ciphers(1)|ciphers(1)>