s_time (1)

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NAME

s_time - SSL/TLS performance timing program

SYNOPSIS

openssl s_time [-connect host:port] [-www page] [-cert filename] [-key filename] [-CApath directory] [-CAfile filename] [-reuse] [-new] [-verify depth] [-nbio] [-time seconds] [-ssl2] [-ssl3] [-bugs] [-cipher cipherlist]

DESCRIPTION

The s_time command implements a generic client which connects to a remote host using It can request a page from the server and includes the time to transfer the payload data in its timing measurements. It measures the number of connections within a given timeframe, the amount of data transferred (if any), and calculates the average time spent for one connection.

OPTIONS

-connect host:port

This specifies the host and optional port to connect to.

-www page

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.

-cert certname

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.

-key keyfile

The private key to use. If not specified then the certificate file will be used. The file is in

PEM

format.

-verify depth

The verify depth to use. This specifies the maximum length of the server certificate chain and turns on server certificate verification. 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 failure.

-CApath directory

The directory to use for server certificate verification. This directory must be in ``hash format'', see verify for more information. These are also used when building the client certificate chain.

-CAfile file

A file containing trusted certificates to use during server authentication and to use when attempting to build the client certificate chain.

-new

performs the timing test using a new session

ID

for each connection. If neither -new nor -reuse are specified, they are both on by default and executed in sequence.

-reuse

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 sequence.

-nbio

turns on non-blocking I/O.

-ssl2, -ssl3

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,

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; others will only support

SSL

v2 and may need the -ssl2 option.

-bugs

there are several known bug in

SSL

and

TLS

implementations. Adding this option enables various workarounds.

-cipher cipherlist

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.

-time length

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 connections s_time can establish.

NOTES

s_time can be used to measure the performance of an connection. To connect to an 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

list'' when it requests a certificate. By using s_client(1) the list can be viewed and checked. However some servers only request client authentication after a specific is requested. To obtain the list in this case it is necessary to use the -prexit option of s_client(1) and send an 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.

BUGS

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 ALSO

s_client(1), s_server(1), ciphers(1)