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 (postfix)
              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
       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.

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)
