Provided by: postfix_3.7.4-2build1_amd64 
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 initializing 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 syslogd(8) or postlogd(8).
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)
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.
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
postlogd(8), Postfix logging
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.
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(8postfix)