TLSMGR(8)						      System Manager's Manual							 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 ini-
       tializing 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
       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.

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  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 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, "postfix/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)