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 initial-
           izing 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 inter-
           nal 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.

    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 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 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.

    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 exter-
                  nal sources.

    MISCELLANEOUS CONTROLS
           config_directory (see 'postconf -d' output)
                  The  default  location of the Postfix main.cf and master.cf con-
                  figuration 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, "post-
                  fix/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.

    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(8)