tlsmgr



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 pro-
       cess  startup  it connects to the entropy source and exchange file, and
       creates or truncates the optional TLS session cache files.


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

       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.

       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.


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 (${config_directory}/prng_exch)
              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.

       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)

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