.\"	$NetBSD: tlsmgr.8,v 1.2.14.1 2023/12/25 12:54:42 martin Exp $
.\"
.TH TLSMGR 8 
.ad
.fi
.SH NAME
tlsmgr
\-
Postfix TLS session cache and PRNG manager
.SH "SYNOPSIS"
.na
.nf
\fBtlsmgr\fR [generic Postfix daemon options]
.SH DESCRIPTION
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.fi
The \fBtlsmgr\fR(8) manages the Postfix TLS session caches.
It stores and retrieves cache entries on request by
\fBsmtpd\fR(8) and \fBsmtp\fR(8) processes, and periodically
removes entries that have expired.

The \fBtlsmgr\fR(8) also manages the PRNG (pseudo random number
generator) pool. It answers queries by the \fBsmtpd\fR(8)
and \fBsmtp\fR(8)
processes to seed their internal PRNG pools.

The \fBtlsmgr\fR(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 \fBtlsmgr\fR(8) service.

The \fBtlsmgr\fR(8) saves the PRNG state to an exchange file
periodically and when the process terminates, and reads
the exchange file when initializing its PRNG.
.SH "SECURITY"
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.nf
.ad
.fi
The \fBtlsmgr\fR(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 \fBtlsmgr\fR(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 \fBtlsmgr\fR(8) no
longer uses root privileges when opening cache files. These
files should now be stored under the Postfix\-owned
\fBdata_directory\fR.  As a migration aid, an attempt to
open a cache file under a non\-Postfix directory is redirected
to the Postfix\-owned \fBdata_directory\fR, and a warning
is logged.
.SH DIAGNOSTICS
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.fi
Problems and transactions are logged to \fBsyslogd\fR(8)
or \fBpostlogd\fR(8).
.SH BUGS
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.fi
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.
.SH "CONFIGURATION PARAMETERS"
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.nf
.ad
.fi
Changes to \fBmain.cf\fR are not picked up automatically,
because \fBtlsmgr\fR(8) is a persistent processes.  Use the
command "\fBpostfix reload\fR" after a configuration change.

The text below provides only a parameter summary. See
\fBpostconf\fR(5) for more details including examples.
.SH "TLS SESSION CACHE"
.na
.nf
.ad
.fi
.IP "\fBlmtp_tls_loglevel (0)\fR"
The LMTP\-specific version of the smtp_tls_loglevel
configuration parameter.
.IP "\fBlmtp_tls_session_cache_database (empty)\fR"
The LMTP\-specific version of the smtp_tls_session_cache_database
configuration parameter.
.IP "\fBlmtp_tls_session_cache_timeout (3600s)\fR"
The LMTP\-specific version of the smtp_tls_session_cache_timeout
configuration parameter.
.IP "\fBsmtp_tls_loglevel (0)\fR"
Enable additional Postfix SMTP client logging of TLS activity.
.IP "\fBsmtp_tls_session_cache_database (empty)\fR"
Name of the file containing the optional Postfix SMTP client
TLS session cache.
.IP "\fBsmtp_tls_session_cache_timeout (3600s)\fR"
The expiration time of Postfix SMTP client TLS session cache
information.
.IP "\fBsmtpd_tls_loglevel (0)\fR"
Enable additional Postfix SMTP server logging of TLS activity.
.IP "\fBsmtpd_tls_session_cache_database (empty)\fR"
Name of the file containing the optional Postfix SMTP server
TLS session cache.
.IP "\fBsmtpd_tls_session_cache_timeout (3600s)\fR"
The expiration time of Postfix SMTP server TLS session cache
information.
.SH "PSEUDO RANDOM NUMBER GENERATOR"
.na
.nf
.ad
.fi
.IP "\fBtls_random_source (see 'postconf -d' output)\fR"
The external entropy source for the in\-memory \fBtlsmgr\fR(8) pseudo
random number generator (PRNG) pool.
.IP "\fBtls_random_bytes (32)\fR"
The number of bytes that \fBtlsmgr\fR(8) reads from $tls_random_source
when (re)seeding the in\-memory pseudo random number generator (PRNG)
pool.
.IP "\fBtls_random_exchange_name (see 'postconf -d' output)\fR"
Name of the pseudo random number generator (PRNG) state file
that is maintained by \fBtlsmgr\fR(8).
.IP "\fBtls_random_prng_update_period (3600s)\fR"
The time between attempts by \fBtlsmgr\fR(8) to save the state of
the pseudo random number generator (PRNG) to the file specified
with $tls_random_exchange_name.
.IP "\fBtls_random_reseed_period (3600s)\fR"
The maximal time between attempts by \fBtlsmgr\fR(8) to re\-seed the
in\-memory pseudo random number generator (PRNG) pool from external
sources.
.SH "MISCELLANEOUS CONTROLS"
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.nf
.ad
.fi
.IP "\fBconfig_directory (see 'postconf -d' output)\fR"
The default location of the Postfix main.cf and master.cf
configuration files.
.IP "\fBdata_directory (see 'postconf -d' output)\fR"
The directory with Postfix\-writable data files (for example:
caches, pseudo\-random numbers).
.IP "\fBdaemon_timeout (18000s)\fR"
How much time a Postfix daemon process may take to handle a
request before it is terminated by a built\-in watchdog timer.
.IP "\fBprocess_id (read\-only)\fR"
The process ID of a Postfix command or daemon process.
.IP "\fBprocess_name (read\-only)\fR"
The process name of a Postfix command or daemon process.
.IP "\fBsyslog_facility (mail)\fR"
The syslog facility of Postfix logging.
.IP "\fBsyslog_name (see 'postconf -d' output)\fR"
A prefix that is prepended to the process name in syslog
records, so that, for example, "smtpd" becomes "prefix/smtpd".
.PP
Available in Postfix 3.3 and later:
.IP "\fBservice_name (read\-only)\fR"
The master.cf service name of a Postfix daemon process.
.SH "SEE ALSO"
.na
.nf
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
.SH "README FILES"
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.nf
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Use "\fBpostconf readme_directory\fR" or
"\fBpostconf html_directory\fR" to locate this information.
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.nf
TLS_README, Postfix TLS configuration and operation
.SH "LICENSE"
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.nf
.ad
.fi
The Secure Mailer license must be distributed with this software.
.SH HISTORY
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This service was introduced with Postfix version 2.2.
.SH "AUTHOR(S)"
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.nf
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