Postfix manual - tlsmgr(8)

    TLSMGR(8)                                                            TLSMGR(8)

    NAME
           tlsmgr - Postfix TLS session cache and PRNG manager

    SYNOPSIS
           tlsmgr [generic Postfix daemon options]

    DESCRIPTION
           The  tlsmgr(8) manages the Postfix TLS session caches.  It
           stores and retrieves cache entries on request by  smtpd(8)
           and  smtp(8)  processes,  and periodically removes entries
           that have expired.

           The tlsmgr(8) also manages the PRNG (pseudo random  number
           generator)  pool.  It  answers queries by the smtpd(8) and
           smtp(8) processes to seed their internal PRNG pools.

           The tlsmgr(8)'s PRNG pool  is  initially  seeded  from  an
           external  source (EGD, /dev/urandom, or regular file).  It
           is updated at configurable  pseudo-random  intervals  with
           data  from the external source. It is updated periodically
           with data from TLS session cache entries and with the time
           of  day,  and  is  updated with the time of day whenever a
           process requests tlsmgr(8) service.

           The tlsmgr(8) saves the PRNG state  to  an  exchange  file
           periodically  and  when  the process terminates, and reads
           the exchange file when initializing its PRNG.

    SECURITY
           The tlsmgr(8) is not  security-sensitive.  The  code  that
           maintains  the  external  and internal PRNG pools does not
           "trust" the data that it manipulates, and  the  code  that
           maintains  the  TLS  session cache does not touch the con-
           tents of the cached entries, except for seeding its inter-
           nal PRNG pool.

           The  tlsmgr(8) can be run chrooted and with reduced privi-
           leges.  At process startup  it  connects  to  the  entropy
           source  and  exchange  file,  and creates or truncates the
           optional TLS session cache files.

           With Postfix version  2.5  and  later,  the  tlsmgr(8)  no
           longer  uses  root  privileges  when  opening cache files.
           These files should now be stored under  the  Postfix-owned
           data_directory.   As a migration aid, an attempt to open a
           cache file under a non-Postfix directory is redirected  to
           the Postfix-owned data_directory, and a warning is logged.

    DIAGNOSTICS
           Problems and transactions are logged to the syslog daemon.

    BUGS
           There is no automatic means to limit the number of entries
           in the TLS session caches and/or the size of the TLS cache
           files.

    CONFIGURATION PARAMETERS
           Changes  to  main.cf  are  not  picked  up  automatically,
           because tlsmgr(8) is a persistent processes.  Use the com-
           mand "postfix reload" after a configuration change.

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

    TLS SESSION CACHE
           lmtp_tls_loglevel (0)
                  The LMTP-specific version of the  smtp_tls_loglevel
                  configuration parameter.

           lmtp_tls_session_cache_database (empty)
                  The  LMTP-specific  version  of  the  smtp_tls_ses-
                  sion_cache_database configuration parameter.

           lmtp_tls_session_cache_timeout (3600s)
                  The  LMTP-specific  version  of  the  smtp_tls_ses-
                  sion_cache_timeout configuration parameter.

           smtp_tls_loglevel (0)
                  Enable  additional  Postfix  SMTP client logging of
                  TLS activity.

           smtp_tls_session_cache_database (empty)
                  Name of the file containing  the  optional  Postfix
                  SMTP client TLS session cache.

           smtp_tls_session_cache_timeout (3600s)
                  The expiration time of Postfix SMTP client TLS ses-
                  sion cache information.

           smtpd_tls_loglevel (0)
                  Enable additional Postfix SMTP  server  logging  of
                  TLS activity.

           smtpd_tls_session_cache_database (empty)
                  Name  of  the  file containing the optional Postfix
                  SMTP server TLS session cache.

           smtpd_tls_session_cache_timeout (3600s)
                  The expiration time of Postfix SMTP server TLS ses-
                  sion cache information.

    PSEUDO RANDOM NUMBER GENERATOR
           tls_random_source (see 'postconf -d' output)
                  The  external  entropy  source  for  the  in-memory
                  tlsmgr(8) pseudo  random  number  generator  (PRNG)
                  pool.

           tls_random_bytes (32)
                  The  number  of  bytes  that  tlsmgr(8)  reads from
                  $tls_random_source when (re)seeding  the  in-memory
                  pseudo random number generator (PRNG) pool.

           tls_random_exchange_name (see 'postconf -d' output)
                  Name  of  the pseudo random number generator (PRNG)
                  state file that is maintained by tlsmgr(8).

           tls_random_prng_update_period (3600s)
                  The time between attempts by tlsmgr(8) to save  the
                  state  of the pseudo random number generator (PRNG)
                  to    the    file    specified    with    $tls_ran-
                  dom_exchange_name.

           tls_random_reseed_period (3600s)
                  The  maximal  time between attempts by tlsmgr(8) to
                  re-seed the in-memory pseudo random number  genera-
                  tor (PRNG) pool from external sources.

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

           data_directory (see 'postconf -d' output)
                  The directory with Postfix-writable data files (for
                  example: caches, pseudo-random numbers).

           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.

           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), Postfix SMTP client
           smtpd(8), Postfix SMTP server
           postconf(5), configuration parameters
           master(5), generic daemon options
           master(8), process manager
           syslogd(8), system logging

    README FILES
           TLS_README, Postfix TLS configuration and operation

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

    AUTHOR(S)
           Lutz Jaenicke
           BTU Cottbus
           Allgemeine Elektrotechnik
           Universitaetsplatz 3-4
           D-03044 Cottbus, Germany

           Adapted by:
           Wietse Venema
           IBM T.J. Watson Research
           P.O. Box 704
           Yorktown Heights, NY 10598, USA

                                                                         TLSMGR(8)