Updated: 2022/Sep/29

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TLSMGR(8)                   System Manager's Manual                  TLSMGR(8)

       tlsmgr - Postfix TLS session cache and PRNG manager

       tlsmgr [generic Postfix daemon options]

       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.

       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 contents of the cached entries, except for seeding its
       internal PRNG pool.

       The tlsmgr(8) can be run chrooted and with reduced privileges.  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.

       Problems and transactions are logged to syslogd(8) or postlogd(8).

       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.

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

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


       lmtp_tls_loglevel (0)
              The LMTP-specific version of the smtp_tls_loglevel configuration

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

       lmtp_tls_session_cache_timeout (3600s)
              The LMTP-specific version of the smtp_tls_session_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 session cache

       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 session cache


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


       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)
              A prefix that is prepended to the process name in syslog
              records, so that, for example, "smtpd" becomes "prefix/smtpd".

       Available in Postfix 3.3 and later:

       service_name (read-only)
              The master.cf service name of a Postfix daemon process.

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

       Use "postconf readme_directory" or "postconf html_directory" to locate
       this information.
       TLS_README, Postfix TLS configuration and operation

       The Secure Mailer license must be distributed with this software.

       This service was introduced with Postfix version 2.2.

       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

       Wietse Venema
       Google, Inc.
       111 8th Avenue
       New York, NY 10011, USA