1TLSMGR(8)                   System Manager's Manual                  TLSMGR(8)
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NAME

6       tlsmgr - Postfix TLS session cache and PRNG manager
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SYNOPSIS

9       tlsmgr [generic Postfix daemon options]
10

DESCRIPTION

12       The  tlsmgr(8)  manages  the Postfix TLS session caches.  It stores and
13       retrieves cache entries on request by smtpd(8) and  smtp(8)  processes,
14       and periodically removes entries that have expired.
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16       The  tlsmgr(8)  also  manages the PRNG (pseudo random number generator)
17       pool. It answers queries by the smtpd(8) and smtp(8) processes to  seed
18       their internal PRNG pools.
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20       The  tlsmgr(8)'s  PRNG pool is initially seeded from an external source
21       (EGD, /dev/urandom, or regular file).  It is  updated  at  configurable
22       pseudo-random  intervals  with  data  from  the  external source. It is
23       updated periodically with data from TLS session cache entries and  with
24       the time of day, and is updated with the time of day whenever a process
25       requests tlsmgr(8) service.
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27       The tlsmgr(8) saves the PRNG state to an exchange file periodically and
28       when  the process terminates, and reads the exchange file when initial‐
29       izing its PRNG.
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SECURITY

32       The tlsmgr(8) is not security-sensitive. The code  that  maintains  the
33       external  and  internal  PRNG  pools  does not "trust" the data that it
34       manipulates, and the code that maintains the TLS session cache does not
35       touch the contents of the cached entries, except for seeding its inter‐
36       nal PRNG pool.
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38       The tlsmgr(8) can be run chrooted  and  with  reduced  privileges.   At
39       process  startup  it  connects to the entropy source and exchange file,
40       and creates or truncates the optional TLS session cache files.
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42       With Postfix version 2.5 and later, the tlsmgr(8) no longer  uses  root
43       privileges  when  opening cache files. These files should now be stored
44       under the Postfix-owned data_directory.  As a migration aid, an attempt
45       to open a cache file under a non-Postfix directory is redirected to the
46       Postfix-owned data_directory, and a warning is logged.
47

DIAGNOSTICS

49       Problems and transactions are logged to syslogd(8) or postlogd(8).
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BUGS

52       There is no automatic means to limit the number of entries in  the  TLS
53       session caches and/or the size of the TLS cache files.
54

CONFIGURATION PARAMETERS

56       Changes  to  main.cf are not picked up automatically, because tlsmgr(8)
57       is a persistent processes.  Use the command "postfix  reload"  after  a
58       configuration change.
59
60       The  text  below provides only a parameter summary. See postconf(5) for
61       more details including examples.
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TLS SESSION CACHE

64       lmtp_tls_loglevel (0)
65              The LMTP-specific version of the smtp_tls_loglevel configuration
66              parameter.
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68       lmtp_tls_session_cache_database (empty)
69              The LMTP-specific version of the smtp_tls_session_cache_database
70              configuration parameter.
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72       lmtp_tls_session_cache_timeout (3600s)
73              The LMTP-specific version of the  smtp_tls_session_cache_timeout
74              configuration parameter.
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76       smtp_tls_loglevel (0)
77              Enable additional Postfix SMTP client logging of TLS activity.
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79       smtp_tls_session_cache_database (empty)
80              Name of the file containing the optional Postfix SMTP client TLS
81              session cache.
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83       smtp_tls_session_cache_timeout (3600s)
84              The expiration time of Postfix SMTP  client  TLS  session  cache
85              information.
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87       smtpd_tls_loglevel (0)
88              Enable additional Postfix SMTP server logging of TLS activity.
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90       smtpd_tls_session_cache_database (empty)
91              Name of the file containing the optional Postfix SMTP server TLS
92              session cache.
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94       smtpd_tls_session_cache_timeout (3600s)
95              The expiration time of Postfix SMTP  server  TLS  session  cache
96              information.
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PSEUDO RANDOM NUMBER GENERATOR

99       tls_random_source (see 'postconf -d' output)
100              The  external  entropy source for the in-memory tlsmgr(8) pseudo
101              random number generator (PRNG) pool.
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103       tls_random_bytes (32)
104              The number of bytes that tlsmgr(8) reads from $tls_random_source
105              when  (re)seeding  the  in-memory pseudo random number generator
106              (PRNG) pool.
107
108       tls_random_exchange_name (see 'postconf -d' output)
109              Name of the pseudo random number  generator  (PRNG)  state  file
110              that is maintained by tlsmgr(8).
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112       tls_random_prng_update_period (3600s)
113              The  time between attempts by tlsmgr(8) to save the state of the
114              pseudo random number generator (PRNG) to the file specified with
115              $tls_random_exchange_name.
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117       tls_random_reseed_period (3600s)
118              The  maximal  time  between attempts by tlsmgr(8) to re-seed the
119              in-memory pseudo random number generator (PRNG) pool from exter‐
120              nal sources.
121

MISCELLANEOUS CONTROLS

123       config_directory (see 'postconf -d' output)
124              The  default  location of the Postfix main.cf and master.cf con‐
125              figuration files.
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127       data_directory (see 'postconf -d' output)
128              The directory with Postfix-writable  data  files  (for  example:
129              caches, pseudo-random numbers).
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131       daemon_timeout (18000s)
132              How  much  time  a  Postfix  daemon process may take to handle a
133              request before it is terminated by a built-in watchdog timer.
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135       process_id (read-only)
136              The process ID of a Postfix command or daemon process.
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138       process_name (read-only)
139              The process name of a Postfix command or daemon process.
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141       syslog_facility (mail)
142              The syslog facility of Postfix logging.
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144       syslog_name (see 'postconf -d' output)
145              A prefix that  is  prepended  to  the  process  name  in  syslog
146              records, so that, for example, "smtpd" becomes "prefix/smtpd".
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148       Available in Postfix 3.3 and later:
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150       service_name (read-only)
151              The master.cf service name of a Postfix daemon process.
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SEE ALSO

154       smtp(8), Postfix SMTP client
155       smtpd(8), Postfix SMTP server
156       postconf(5), configuration parameters
157       master(5), generic daemon options
158       master(8), process manager
159       postlogd(8), Postfix logging
160       syslogd(8), system logging
161

README FILES

163       Use  "postconf readme_directory" or "postconf html_directory" to locate
164       this information.
165       TLS_README, Postfix TLS configuration and operation
166

LICENSE

168       The Secure Mailer license must be distributed with this software.
169

HISTORY

171       This service was introduced with Postfix version 2.2.
172

AUTHOR(S)

174       Lutz Jaenicke
175       BTU Cottbus
176       Allgemeine Elektrotechnik
177       Universitaetsplatz 3-4
178       D-03044 Cottbus, Germany
179
180       Adapted by:
181       Wietse Venema
182       IBM T.J. Watson Research
183       P.O. Box 704
184       Yorktown Heights, NY 10598, USA
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186       Wietse Venema
187       Google, Inc.
188       111 8th Avenue
189       New York, NY 10011, USA
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193                                                                     TLSMGR(8)
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