tlsmgr - Postfix TLS session cache and PRNG manager

       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)

       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 "postfixreload" after a configuration change.

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

       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.

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

       This service was introduced with Postfix version 2.2.

       The Secure Mailer license must be distributed with this software.

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.

       tlsmgr - Postfix TLS session cache and PRNG manager

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.

       Use "postconfreadme_directory" or "postconfhtml_directory" to locate this information.
       TLS_README, Postfix TLS configuration and operation

       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.

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

tlsmgr [generic Postfix daemon options]

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 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 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.