1MASTER(5)                     File Formats Manual                    MASTER(5)
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NAME

6       master - Postfix master process configuration file format
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DESCRIPTION

9       The  Postfix  mail  system  is  implemented by small number of (mostly)
10       client commands that are invoked by users, and by a  larger  number  of
11       services that run in the background.
12
13       Postfix  services are implemented by daemon processes. These run in the
14       background under control of the master(8) process.  The master.cf  con‐
15       figuration file defines how a client program connects to a service, and
16       what daemon program runs when a service is requested.  Most daemon pro‐
17       cesses  are short-lived and terminate voluntarily after serving max_use
18       clients, or after inactivity for max_idle or more units of time.
19
20       All daemons specified here must speak a Postfix-internal  protocol.  In
21       order  to  execute  non-Postfix  software  use the local(8), pipe(8) or
22       spawn(8) services, or run the  server  under  control  by  inetd(8)  or
23       equivalent.
24
25       After  changing  master.cf  you must execute "postfix reload" to reload
26       the configuration.
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SYNTAX

29       The general format of the master.cf file is as follows:
30
31       ·      Empty lines and whitespace-only lines are ignored, as are  lines
32              whose first non-whitespace character is a `#'.
33
34       ·      A  logical  line  starts  with  non-whitespace text. A line that
35              starts with whitespace continues a logical line.
36
37       ·      Each logical line defines a single Postfix service.   Each  ser‐
38              vice  is  identified  by  its  name and type as described below.
39              When multiple lines specify the same service name and type, only
40              the  last  one is remembered.  Otherwise, the order of master.cf
41              service definitions does not matter.
42
43       Each logical line consists of eight  fields  separated  by  whitespace.
44       These  are described below in the order as they appear in the master.cf
45       file.
46
47       Where applicable a field of "-"  requests  that  the  built-in  default
48       value  be  used.  For boolean fields specify "y" or "n" to override the
49       default value.
50
51       Service name
52              The service name syntax depends on the service type as described
53              next.
54
55       Service type
56              Specify one of the following service types:
57
58              inet   The  service listens on a TCP/IP socket and is accessible
59                     via the network.
60
61                     The service name is specified as host:port, denoting  the
62                     host   and  port  on  which  new  connections  should  be
63                     accepted. The host  part  (and  colon)  may  be  omitted.
64                     Either  host  or port may be given in symbolic form (host
65                     or service name) or in numeric form (IP address  or  port
66                     number).   Host  information may be enclosed inside "[]",
67                     but this form is not necessary.
68
69                     Examples: a  service  named  127.0.0.1:smtp  or  ::1:smtp
70                     receives mail via the loopback interface only; and a ser‐
71                     vice named 10025 accepts connections on  TCP  port  10025
72                     via  all  interfaces  configured with the inet_interfaces
73                     parameter.
74
75
76                     Note:  with  Postfix  version  2.2  and   later   specify
77                     "inet_interfaces  = loopback-only" in main.cf, instead of
78                     hard-coding loopback IP address information in  master.cf
79                     or in main.cf.
80
81              unix   The service listens on a UNIX-domain socket and is acces‐
82                     sible for local clients only.
83
84                     The service name is a pathname relative  to  the  Postfix
85                     queue    directory    (pathname   controlled   with   the
86                     queue_directory configuration parameter in main.cf).
87
88                     On Solaris systems the  unix  type  is  implemented  with
89                     streams sockets.
90
91              fifo   The  service listens on a FIFO (named pipe) and is acces‐
92                     sible for local clients only.
93
94                     The service name is a pathname relative  to  the  Postfix
95                     queue    directory    (pathname   controlled   with   the
96                     queue_directory configuration parameter in main.cf).
97
98              pass   The service listens  on  a  UNIX-domain  socket,  and  is
99                     accessible  to  local  clients only. It receives one open
100                     connection  (file  descriptor  passing)  per   connection
101                     request.
102
103                     The  service  name  is a pathname relative to the Postfix
104                     queue   directory   (pathname   controlled    with    the
105                     queue_directory configuration parameter in main.cf).
106
107                     On  Solaris  systems  the  pass  type is implemented with
108                     streams sockets.
109
110                     This feature is available as of Postfix version 2.5.
111
112       Private (default: y)
113              Whether or not access is restricted to the mail system.   Inter‐
114              net (type inet) services can't be private.
115
116       Unprivileged (default: y)
117              Whether the service runs with root privileges or as the owner of
118              the  Postfix  system  (the  owner  name  is  controlled  by  the
119              mail_owner configuration variable in the main.cf file).
120
121              The  local(8), pipe(8), spawn(8), and virtual(8) daemons require
122              privileges.
123
124       Chroot (default: y)
125              Whether or not the service  runs  chrooted  to  the  mail  queue
126              directory (pathname is controlled by the queue_directory config‐
127              uration variable in the main.cf file).
128
129              Chroot should not be used with the local(8), pipe(8),  spawn(8),
130              and virtual(8) daemons.  Although the proxymap(8) server can run
131              chrooted, doing so defeats most of the purpose  of  having  that
132              service in the first place.
133
134              The files in the examples/chroot-setup subdirectory of the Post‐
135              fix source archive show set up a Postfix chroot environment on a
136              variety  of  systems.  See  also  BASIC_CONFIGURATION_README for
137              issues related to running daemons chrooted.
138
139       Wake up time (default: 0)
140              Automatically wake up the named service after the specified num‐
141              ber  of seconds. The wake up is implemented by connecting to the
142              service and sending a wake up request.  A ? at the  end  of  the
143              wake-up  time  field  requests  that  no  wake up events be sent
144              before the first time a service is used.  Specify 0 for no auto‐
145              matic wake up.
146
147              The  pickup(8),  qmgr(8)  and flush(8) daemons require a wake up
148              timer.
149
150       Process limit (default: $default_process_limit)
151              The maximum number of processes that may  execute  this  service
152              simultaneously. Specify 0 for no process count limit.
153
154              NOTE:  Some  Postfix  services  must  be configured as a single-
155              process service (for example, qmgr(8)) and some services must be
156              configured  with  no  process  limit  (for example, cleanup(8)).
157              These limits must not be changed.
158
159       Command name + arguments
160              The command to be executed.  Characters that are special to  the
161              shell  such  as  ">"  or  "|"  have no special meaning here, and
162              quotes cannot be used to  protect  arguments  containing  white‐
163              space.
164
165              The  command  name  is  relative to the Postfix daemon directory
166              (pathname is controlled by  the  daemon_directory  configuration
167              variable).
168
169              The  command  argument syntax for specific commands is specified
170              in the respective daemon manual page.
171
172              The following command-line options have the same effect for  all
173              daemon programs:
174
175              -D     Run  the  daemon  under  control by the command specified
176                     with the debugger_command variable in the main.cf config‐
177                     uration file.  See DEBUG_README for hints and tips.
178
179              -o name=value
180                     Override  the  named main.cf configuration parameter. The
181                     parameter value can refer to other  parameters  as  $name
182                     etc., just like in main.cf.  See postconf(5) for syntax.
183
184                     NOTE  1:  do  not specify whitespace around the "=" or in
185                     parameter values. To specify a parameter value that  con‐
186                     tains  whitespace, use commas instead of spaces, or spec‐
187                     ify the value in main.cf. Example:
188
189                     /etc/postfix/master.cf:
190                         submission inet .... smtpd
191                             -o smtpd_mumble=$submission_mumble
192
193                     /etc/postfix/main.cf
194                         submission_mumble = text with whitespace...
195
196                     NOTE 2: Over-zealous use of parameter overrides makes the
197                     Postfix  configuration  hard  to understand and maintain.
198                     At a certain point, it might be easier to configure  mul‐
199                     tiple instances of Postfix, instead of configuring multi‐
200                     ple personalities via master.cf.
201
202              -v     Increase the verbose logging level. Specify  multiple  -v
203                     options  to  make  a  Postfix daemon process increasingly
204                     verbose.
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SEE ALSO

207       master(8), process manager
208       postconf(5), configuration parameters
209

README FILES

211       Use "postconf readme_directory" or "postconf html_directory" to  locate
212       this information.
213       BASIC_CONFIGURATION_README, basic configuration
214       DEBUG_README, Postfix debugging
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LICENSE

217       The Secure Mailer license must be distributed with this software.
218

AUTHOR(S)

220       Initial version by
221       Magnus Baeck
222       Lund Institute of Technology
223       Sweden
224
225       Wietse Venema
226       IBM T.J. Watson Research
227       P.O. Box 704
228       Yorktown Heights, NY 10598, USA
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