postfix-master/scache.8.html

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   7 SCACHE(8)                                                            SCACHE(8)
   8
   9 <b>NAME</b>
  10        scache - Postfix shared connection cache server
  11
  12 <b>SYNOPSIS</b>
  13        <b>scache</b> [generic Postfix daemon options]
  14
  15 <b>DESCRIPTION</b>
  16        The  <a href="scache.8.html"><b>scache</b>(8)</a>  server maintains a shared multi-connection
  17        cache. This information can be used by, for example, Post-
  18        fix SMTP clients or other Postfix delivery agents.
  19
  20        The connection cache is organized into logical destination
  21        names, physical endpoint names, and connections.
  22
  23        As a specific example, logical SMTP  destinations  specify
  24        (transport,  domain,  port),  and  physical SMTP endpoints
  25        specify (transport, IP address, port).  An SMTP connection
  26        may be saved after a successful mail transaction.
  27
  28        In  the general case, one logical destination may refer to
  29        zero or more physical endpoints, one physical endpoint may
  30        be  referenced  by  zero or more logical destinations, and
  31        one endpoint may refer to zero or more connections.
  32
  33        The exact syntax of a logical destination or endpoint name
  34        is  application  dependent;  the <a href="scache.8.html"><b>scache</b>(8)</a> server does not
  35        care.   A  connection  is  stored  as  a  file  descriptor
  36        together  with  application-dependent  information that is
  37        needed to re-activate  a  connection  object.  Again,  the
  38        <a href="scache.8.html"><b>scache</b>(8)</a>  server  is completely unaware of the details of
  39        that information.
  40
  41        All information is stored  with  a  finite  time  to  live
  42        (ttl).   The  connection  cache  daemon terminates when no
  43        client is connected for <b><a href="postconf.5.html#max_idle">max_idle</a></b> time units.
  44
  45        This server implements the following requests:
  46
  47        <b>save_endp</b> <i>ttl endpoint endpoint</i><b>_</b><i>properties file</i><b>_</b><i>descriptor</i>
  48               Save the specified file descriptor  and  connection
  49               property  data  under  the specified endpoint name.
  50               The endpoint properties are used by the  client  to
  51               re-activate a passivated connection object.
  52
  53        <b>find_endp</b> <i>endpoint</i>
  54               Look   up  cached  properties  and  a  cached  file
  55               descriptor for the specified endpoint.
  56
  57        <b>save_dest</b> <i>ttl destination destination</i><b>_</b><i>properties endpoint</i>
  58               Save the binding between a logical destination  and
  59               an  endpoint  under  the destination name, together
  60               with destination  specific  connection  properties.
  61               The  destination  properties are used by the client
  62               to re-activate a passivated connection object.
  63
  64        <b>find_dest</b> <i>destination</i>
  65               Look up cached destination properties, cached  end-
  66               point  properties, and a cached file descriptor for
  67               the specified logical destination.
  68
  69 <b>SECURITY</b>
  70        The <a href="scache.8.html"><b>scache</b>(8)</a> server is not  security-sensitive.  It  does
  71        not  talk  to  the  network, and it does not talk to local
  72        users.  The <a href="scache.8.html"><b>scache</b>(8)</a> server can run chrooted at fixed low
  73        privilege.
  74
  75        The <a href="scache.8.html"><b>scache</b>(8)</a> server is not a trusted process. It must not
  76        be used to store information that is security sensitive.
  77
  78 <b>DIAGNOSTICS</b>
  79        Problems and transactions are logged to <b>syslogd</b>(8).
  80
  81 <b>BUGS</b>
  82        The  session  cache  cannot  be  shared   among   multiple
  83        machines.
  84
  85        When  a  connection  expires  from the cache, it is closed
  86        without the appropriate protocol specific handshake.
  87
  88 <b>CONFIGURATION PARAMETERS</b>
  89        Changes  to  <a href="postconf.5.html"><b>main.cf</b></a>  are  picked  up   automatically   as
  90        <a href="scache.8.html"><b>scache</b>(8)</a> processes run for only a limited amount of time.
  91        Use the command "<b>postfix reload</b>" to speed up a change.
  92
  93        The text below provides  only  a  parameter  summary.  See
  94        <a href="postconf.5.html"><b>postconf</b>(5)</a> for more details including examples.
  95
  96 <b>RESOURCE CONTROLS</b>
  97        <b><a href="postconf.5.html#connection_cache_ttl_limit">connection_cache_ttl_limit</a> (2s)</b>
  98               The  maximal  time-to-live value that the <a href="scache.8.html"><b>scache</b>(8)</a>
  99               connection cache server allows.
 100
 101        <b><a href="postconf.5.html#connection_cache_status_update_time">connection_cache_status_update_time</a> (600s)</b>
 102               How frequently the <a href="scache.8.html"><b>scache</b>(8)</a> server logs usage sta-
 103               tistics  with  connection  cache hit and miss rates
 104               for logical  destinations  and  for  physical  end-
 105               points.
 106
 107 <b>MISCELLANEOUS CONTROLS</b>
 108        <b><a href="postconf.5.html#config_directory">config_directory</a> (see 'postconf -d' output)</b>
 109               The  default  location  of  the Postfix <a href="postconf.5.html">main.cf</a> and
 110               <a href="master.5.html">master.cf</a> configuration files.
 111
 112        <b><a href="postconf.5.html#daemon_timeout">daemon_timeout</a> (18000s)</b>
 113               How much time a Postfix daemon process may take  to
 114               handle  a  request  before  it  is  terminated by a
 115               built-in watchdog timer.
 116
 117        <b><a href="postconf.5.html#ipc_timeout">ipc_timeout</a> (3600s)</b>
 118               The time limit for sending or receiving information
 119               over an internal communication channel.
 120
 121        <b><a href="postconf.5.html#max_idle">max_idle</a> (100s)</b>
 122               The  maximum  amount  of  time that an idle Postfix
 123               daemon process waits  for  an  incoming  connection
 124               before terminating voluntarily.
 125
 126        <b><a href="postconf.5.html#process_id">process_id</a> (read-only)</b>
 127               The  process  ID  of  a  Postfix  command or daemon
 128               process.
 129
 130        <b><a href="postconf.5.html#process_name">process_name</a> (read-only)</b>
 131               The process name of a  Postfix  command  or  daemon
 132               process.
 133
 134        <b><a href="postconf.5.html#syslog_facility">syslog_facility</a> (mail)</b>
 135               The syslog facility of Postfix logging.
 136
 137        <b><a href="postconf.5.html#syslog_name">syslog_name</a> (see 'postconf -d' output)</b>
 138               The  mail  system  name  that  is  prepended to the
 139               process name in syslog  records,  so  that  "smtpd"
 140               becomes, for example, "postfix/smtpd".
 141
 142 <b>SEE ALSO</b>
 143        <a href="smtp.8.html">smtp(8)</a>, SMTP client
 144        <a href="postconf.5.html">postconf(5)</a>, configuration parameters
 145        <a href="master.8.html">master(8)</a>, process manager
 146        syslogd(8), system logging
 147
 148 <b>README FILES</b>
 149        <a href="CONNECTION_CACHE_README.html">CONNECTION_CACHE_README</a>, Postfix connection cache
 150
 151 <b>LICENSE</b>
 152        The Secure Mailer license must be  distributed  with  this
 153        software.
 154
 155 <b>HISTORY</b>
 156        This service was introduced with Postfix version 2.2.
 157
 158 <b>AUTHOR(S)</b>
 159        Wietse Venema
 160        IBM T.J. Watson Research
 161        P.O. Box 704
 162        Yorktown Heights, NY 10598, USA
 163
 164                                                                      SCACHE(8)
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