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 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 con-
tents of the cached entries, except for seeding its inter-
nal PRNG pool.
The tlsmgr(8) can be run chrooted and with reduced privi-
leges. At process 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 com-
mand "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 ses-
sion 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 ses-
sion 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_ran-
dom_exchange_name.
tls_random_reseed_period (3600s)
The maximal time between attempts by tlsmgr(8) to
re-seed the in-memory pseudo random number genera-
tor (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.
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 pro-
cess.
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 pro-
cess 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
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)