9 Postfix TLS session cache and PRNG manager
13 \fBtlsmgr\fR [generic Postfix daemon options]
17 The \fBtlsmgr\fR(8) manages the Postfix TLS session caches.
18 It stores and retrieves cache entries on request by
19 \fBsmtpd\fR(8) and \fBsmtp\fR(8) processes, and periodically
20 removes entries that have expired.
22 The \fBtlsmgr\fR(8) also manages the PRNG (pseudo random number
23 generator) pool. It answers queries by the \fBsmtpd\fR(8)
25 processes to seed their internal PRNG pools.
27 The \fBtlsmgr\fR(8)'s PRNG pool is initially seeded from
28 an external source (EGD, /dev/urandom, or regular file).
29 It is updated at configurable pseudo-random intervals with
30 data from the external source. It is updated periodically
31 with data from TLS session cache entries and with the time
32 of day, and is updated with the time of day whenever a
33 process requests \fBtlsmgr\fR(8) service.
35 The \fBtlsmgr\fR(8) saves the PRNG state to an exchange file
36 periodically and when the process terminates, and reads
37 the exchange file when initializing its PRNG.
43 The \fBtlsmgr\fR(8) is not security-sensitive. The code that maintains
44 the external and internal PRNG pools does not "trust" the
45 data that it manipulates, and the code that maintains the
46 TLS session cache does not touch the contents of the cached
47 entries, except for seeding its internal PRNG pool.
49 The \fBtlsmgr\fR(8) can be run chrooted and with reduced privileges.
50 At process startup it connects to the entropy source and
51 exchange file, and creates or truncates the optional TLS
54 With Postfix version 2.5 and later, the \fBtlsmgr\fR(8) no
55 longer uses root privileges when opening cache files. These
56 files should now be stored under the Postfix-owned
57 \fBdata_directory\fR. As a migration aid, an attempt to
58 open a cache file under a non-Postfix directory is redirected
59 to the Postfix-owned \fBdata_directory\fR, and a warning
64 Problems and transactions are logged to the syslog daemon.
68 There is no automatic means to limit the number of entries in the
69 TLS session caches and/or the size of the TLS cache files.
70 .SH "CONFIGURATION PARAMETERS"
75 Changes to \fBmain.cf\fR are not picked up automatically,
76 because \fBtlsmgr\fR(8) is a persistent processes. Use the
77 command "\fBpostfix reload\fR" after a configuration change.
79 The text below provides only a parameter summary. See
80 \fBpostconf\fR(5) for more details including examples.
81 .SH "TLS SESSION CACHE"
86 .IP "\fBlmtp_tls_loglevel (0)\fR"
87 The LMTP-specific version of the smtp_tls_loglevel
88 configuration parameter.
89 .IP "\fBlmtp_tls_session_cache_database (empty)\fR"
90 The LMTP-specific version of the smtp_tls_session_cache_database
91 configuration parameter.
92 .IP "\fBlmtp_tls_session_cache_timeout (3600s)\fR"
93 The LMTP-specific version of the smtp_tls_session_cache_timeout
94 configuration parameter.
95 .IP "\fBsmtp_tls_loglevel (0)\fR"
96 Enable additional Postfix SMTP client logging of TLS activity.
97 .IP "\fBsmtp_tls_session_cache_database (empty)\fR"
98 Name of the file containing the optional Postfix SMTP client
100 .IP "\fBsmtp_tls_session_cache_timeout (3600s)\fR"
101 The expiration time of Postfix SMTP client TLS session cache
103 .IP "\fBsmtpd_tls_loglevel (0)\fR"
104 Enable additional Postfix SMTP server logging of TLS activity.
105 .IP "\fBsmtpd_tls_session_cache_database (empty)\fR"
106 Name of the file containing the optional Postfix SMTP server
108 .IP "\fBsmtpd_tls_session_cache_timeout (3600s)\fR"
109 The expiration time of Postfix SMTP server TLS session cache
111 .SH "PSEUDO RANDOM NUMBER GENERATOR"
116 .IP "\fBtls_random_source (see 'postconf -d' output)\fR"
117 The external entropy source for the in-memory \fBtlsmgr\fR(8) pseudo
118 random number generator (PRNG) pool.
119 .IP "\fBtls_random_bytes (32)\fR"
120 The number of bytes that \fBtlsmgr\fR(8) reads from $tls_random_source
121 when (re)seeding the in-memory pseudo random number generator (PRNG)
123 .IP "\fBtls_random_exchange_name (see 'postconf -d' output)\fR"
124 Name of the pseudo random number generator (PRNG) state file
125 that is maintained by \fBtlsmgr\fR(8).
126 .IP "\fBtls_random_prng_update_period (3600s)\fR"
127 The time between attempts by \fBtlsmgr\fR(8) to save the state of
128 the pseudo random number generator (PRNG) to the file specified
129 with $tls_random_exchange_name.
130 .IP "\fBtls_random_reseed_period (3600s)\fR"
131 The maximal time between attempts by \fBtlsmgr\fR(8) to re-seed the
132 in-memory pseudo random number generator (PRNG) pool from external
134 .SH "MISCELLANEOUS CONTROLS"
139 .IP "\fBconfig_directory (see 'postconf -d' output)\fR"
140 The default location of the Postfix main.cf and master.cf
142 .IP "\fBdata_directory (see 'postconf -d' output)\fR"
143 The directory with Postfix-writable data files (for example:
144 caches, pseudo-random numbers).
145 .IP "\fBdaemon_timeout (18000s)\fR"
146 How much time a Postfix daemon process may take to handle a
147 request before it is terminated by a built-in watchdog timer.
148 .IP "\fBprocess_id (read-only)\fR"
149 The process ID of a Postfix command or daemon process.
150 .IP "\fBprocess_name (read-only)\fR"
151 The process name of a Postfix command or daemon process.
152 .IP "\fBsyslog_facility (mail)\fR"
153 The syslog facility of Postfix logging.
154 .IP "\fBsyslog_name (see 'postconf -d' output)\fR"
155 The mail system name that is prepended to the process name in syslog
156 records, so that "smtpd" becomes, for example, "postfix/smtpd".
160 smtp(8), Postfix SMTP client
161 smtpd(8), Postfix SMTP server
162 postconf(5), configuration parameters
163 master(5), generic daemon options
164 master(8), process manager
165 syslogd(8), system logging
171 Use "\fBpostconf readme_directory\fR" or
172 "\fBpostconf html_directory\fR" to locate this information.
175 TLS_README, Postfix TLS configuration and operation
181 The Secure Mailer license must be distributed with this software.
187 Allgemeine Elektrotechnik
188 Universitaetsplatz 3-4
189 D-03044 Cottbus, Germany
193 IBM T.J. Watson Research
195 Yorktown Heights, NY 10598, USA