Страницы справочника OS X

Эта страница руководства для  версии 10.9 Mac OS X

Читать страницы руководства

SCACHE(8)                                                                                          SCACHE(8)



NAME
       scache - Postfix shared connection cache server

SYNOPSIS
       scache [generic Postfix daemon options]

DESCRIPTION
       The  scache(8) server maintains a shared multi-connection cache. This information can be used by, for
       example, Postfix SMTP clients or other Postfix delivery agents.

       The connection cache is organized into logical destination names, physical endpoint names,  and  con-nections. connections.
       nections.

       As a specific example, logical SMTP destinations specify (transport, domain, port), and physical SMTP
       endpoints specify (transport, IP address, port).  An SMTP connection may be saved after a  successful
       mail transaction.

       In the general case, one logical destination may refer to zero or more physical endpoints, one physi-cal physical
       cal endpoint may be referenced by zero or more logical destinations, and one endpoint  may  refer  to
       zero or more connections.

       The  exact  syntax  of a logical destination or endpoint name is application dependent; the scache(8)
       server does not care.  A connection is stored as a file descriptor together  with  application-depen-dent application-dependent
       dent  information  that  is needed to re-activate a connection object. Again, the scache(8) server is
       completely unaware of the details of that information.

       All information is stored with a finite time to live (ttl).  The connection cache  daemon  terminates
       when no client is connected for max_idle time units.

       This server implements the following requests:

       save_endp ttl endpoint endpoint_properties file_descriptor
              Save  the  specified file descriptor and connection property data under the specified endpoint
              name. The endpoint properties are used by the client to re-activate  a  passivated  connection
              object.

       find_endp endpoint
              Look up cached properties and a cached file descriptor for the specified endpoint.

       save_dest ttl destination destination_properties endpoint
              Save  the  binding  between  a logical destination and an endpoint under the destination name,
              together with destination specific connection properties. The destination properties are  used
              by the client to re-activate a passivated connection object.

       find_dest destination
              Look  up cached destination properties, cached endpoint properties, and a cached file descrip-tor descriptor
              tor for the specified logical destination.

SECURITY
       The scache(8) server is not security-sensitive. It does not talk to the network, and it does not talk
       to local users.  The scache(8) server can run chrooted at fixed low privilege.

       The scache(8) server is not a trusted process. It must not be used to store information that is secu-rity security
       rity sensitive.

DIAGNOSTICS
       Problems and transactions are logged to syslogd(8).

BUGS
       The session cache cannot be shared among multiple machines.

       When a connection expires from the cache, it is closed  without  the  appropriate  protocol  specific
       handshake.

CONFIGURATION PARAMETERS
       Changes  to  main.cf are picked up automatically as scache(8) processes run for only a limited amount
       of time. Use the command "postfix reload" to speed up a change.

       The text below provides only a parameter summary. See postconf(5) for more  details  including  exam-ples. examples.
       ples.

RESOURCE CONTROLS
       connection_cache_ttl_limit (2s)
              The maximal time-to-live value that the scache(8) connection cache server allows.

       connection_cache_status_update_time (600s)
              How  frequently  the scache(8) server logs usage statistics with connection cache hit and miss
              rates for logical destinations and for physical endpoints.

MISCELLANEOUS CONTROLS
       config_directory (see 'postconf -d' output)
              The default location of the Postfix main.cf and master.cf configuration files.

       daemon_timeout (18000s)
              How much time a Postfix daemon process may take to handle a request before it is terminated by
              a built-in watchdog timer.

       ipc_timeout (3600s)
              The time limit for sending or receiving information over an internal communication channel.

       max_idle (100s)
              The  maximum  amount of time that an idle Postfix daemon process waits for an incoming connec-tion connection
              tion before terminating voluntarily.

       process_id (read-only)
              The process ID of a Postfix command or daemon process.

       process_name (read-only)
              The process name of a Postfix command or daemon process.

       syslog_facility (mail)
              The syslog facility of Postfix logging.

       syslog_name (see 'postconf -d' output)
              The mail system name that is prepended to the process name in syslog records, so that  "smtpd"
              becomes, for example, "postfix/smtpd".

SEE ALSO
       smtp(8), SMTP client
       postconf(5), configuration parameters
       master(8), process manager
       syslogd(8), system logging

README FILES
       Use "postconf readme_directory" or "postconf html_directory" to locate this information.
       CONNECTION_CACHE_README, Postfix connection cache

LICENSE
       The Secure Mailer license must be distributed with this software.

HISTORY
       This service was introduced with Postfix version 2.2.

AUTHOR(S)
       Wietse Venema
       IBM T.J. Watson Research
       P.O. Box 704
       Yorktown Heights, NY 10598, USA



                                                                                                   SCACHE(8)