man > tlsmgr(8postfix)

TLSMGR(8postfix)                                                                    TLSMGR(8postfix)

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  ex‐
       pired.

       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  ex‐
       ternal  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 ter‐
       minates, 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 contents of the cached entries, except for seeding  its  in‐
       ternal PRNG pool.

       The  tlsmgr(8)  can  be run chrooted and with reduced privileges.  At process startup it con‐
       nects to the entropy source and exchange file, and creates or truncates the optional TLS ses‐
       sion 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 syslogd(8) or postlogd(8).

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 command "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_session_cache_database configuration parame‐
              ter.

       lmtp_tls_session_cache_timeout (3600s)
              The LMTP-specific version of the smtp_tls_session_cache_timeout configuration  parame‐
              ter.

       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 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 session 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_random_exchange_name.

       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.

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  ter‐
              minated 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 exam‐
              ple, "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.

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
       postlogd(8), Postfix logging
       syslogd(8), system logging

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

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

HISTORY
       This service was introduced with Postfix version 2.2.

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

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

                                                                                    TLSMGR(8postfix)