S_TIME(1) OpenSSL S_TIME(1)NAMEs_time - SSL/TLS performance timing program
openssl s_time [-connect host:port] [-www page] [-cert filename] [-key
filename] [-CApath directory] [-CAfile filename] [-reuse] [-new] [-ver‐
ify depth] [-nbio] [-time seconds] [-ssl2] [-ssl3] [-bugs] [-cipher
The s_client command implements a generic SSL/TLS client which connects
to a remote host using SSL/TLS. It can request a page from the server
and includes the time to transfer the payload data in its timing mea‐
surements. It measures the number of connections within a given time‐
frame, the amount of data transferred (if any), and calculates the
average time spent for one connection.
This specifies the host and optional port to connect to.
This specifies the page to GET from the server. A value of '/' gets
the index.htm[l] page. If this parameter is not specified, then
s_time will only perform the handshake to establish SSL connections
but not transfer any payload data.
The certificate to use, if one is requested by the server. The
default is not to use a certificate. The file is in PEM format.
The private key to use. If not specified then the certificate file
will be used. The file is in PEM format.
The verify depth to use. This specifies the maximum length of the
server certificate chain and turns on server certificate verifica‐
tion. Currently the verify operation continues after errors so all
the problems with a certificate chain can be seen. As a side effect
the connection will never fail due to a server certificate verify
The directory to use for server certificate verification. This
directory must be in "hash format", see verify for more informa‐
tion. These are also used when building the client certificate
A file containing trusted certificates to use during server authen‐
tication and to use when attempting to build the client certificate
performs the timing test using a new session ID for each connec‐
tion. If neither -new nor -reuse are specified, they are both on
by default and executed in sequence.
performs the timing test using the same session ID; this can be
used as a test that session caching is working. If neither -new nor
-reuse are specified, they are both on by default and executed in
turns on non-blocking I/O.
these options disable the use of certain SSL or TLS protocols. By
default the initial handshake uses a method which should be compat‐
ible with all servers and permit them to use SSL v3, SSL v2 or TLS
as appropriate. The timing program is not as rich in options to
turn protocols on and off as the s_client(1) program and may not
connect to all servers.
Unfortunately there are a lot of 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 with the -ssl3 option; oth‐
ers will only support SSL v2 and may need the -ssl2 option.
there are several known bug in SSL and TLS implementations. Adding
this option enables various workarounds.
this allows the cipher list sent by the client to be modified.
Although the server determines which cipher suite is used it should
take the first supported cipher in the list sent by the client.
See the ciphers(1) command for more information.
specifies how long (in seconds) s_time should establish connections
and optionally transfer payload data from a server. Server and
client performance and the link speed determine how many connec‐
tions s_time can establish.
s_client can be used to measure the performance of an SSL connection.
To connect to an SSL HTTP server and get the default page the command
openssl s_time-connect servername:443 -www / -CApath yourdir -CAfile yourfile.pem -cipher commoncipher [-ssl3]
would typically be used (https uses port 443). 'commoncipher' is a
cipher to which both client and server can agree, see the ciphers(1)
command for details.
If the handshake fails then there are several possible causes, if it is
nothing obvious like no client certificate then the -bugs, -ssl2, -ssl3
options can be tried in case it is a buggy server. In particular you
should play with these options before submitting a bug report to an
OpenSSL mailing list.
A frequent problem when attempting to get client certificates working
is that a web client complains it has no certificates or gives an empty
list to choose from. This is normally because the server is not sending
the clients certificate authority in its "acceptable CA list" when it
requests a certificate. By using s_client(1) the CA list can be viewed
and checked. However some servers only request client authentication
after a specific URL is requested. To obtain the list in this case it
is necessary to use the -prexit option of s_client(1) and send an HTTP
request for an appropriate page.
If a certificate is specified on the command line using the -cert
option it will not be used unless the server specifically requests a
client certificate. Therefor merely including a client certificate on
the command line is no guarantee that the certificate works.
Because this program does not have all the options of the s_client(1)
program to turn protocols on and off, you may not be able to measure
the performance of all protocols with all servers.
The -verify option should really exit if the server verification fails.
SEE ALSOs_client(1), s_server(1), ciphers(1)0.9.7d 2004-05-17 S_TIME(1)