1opendmarc(8) System Manager's Manual opendmarc(8)
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6 opendmarc - DMARC email policy filter for MTAs
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9 opendmarc [-A] [-c configfile] [-f] [-l] [-n] [-p socketspec] [-P pid‐
10 file] [-t file[,file[...]]] [-u userid[:group]] [-v] [-V]
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13 opendmarc implements the proposed DMARC specification for authentica‐
14 tion of message and reporting of observed traffic.
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16 opendmarc uses the milter interface, originally distributed as part of
17 version 8.11 of sendmail(8), to provide a DMARC processing service for
18 mail transiting a milter-aware MTA.
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20 Most, if not all, of the command line options listed below can also be
21 set using a configuration file. See the -c option for details.
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23 opendmarc relies on addition of Authentication-Results fields by
24 upsteam filters on trusted hosts to collect input to the DMARC algo‐
25 rithm. It does not itself do DKIM or SPF evaluation.
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28 -A Automatically re-start on failures. Use with caution; if the
29 filter fails instantly after it starts, this can cause a tight
30 fork(2) loop. This can be mitigated using some values in the
31 configuration file to limit restarting. See opendmarc.conf(5).
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33 -c configfile
34 Read the named configuration file. See the opendmarc.conf(5)
35 man page for details. Values in the configuration file are
36 overridden when their equivalents are provided on the command
37 line until a configuration reload occurs. The OPERATION section
38 describes how reloads are triggered. The default is to read a
39 configuration file from /etc/opendmarc.conf if one exists, or
40 otherwise to apply defaults to all values.
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42 -f Normally opendmarc forks and exits immediately, leaving the ser‐
43 vice running in the background. This flag suppresses that be‐
44 haviour so that it runs in the foreground.
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46 -l Log via calls to syslog(3) any interesting activity.
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48 -n Parse the configuration file and command line arguments, report‐
49 ing any errors found, and then exit. The exit value will be 0
50 if the filter would start up without complaint, or non-zero oth‐
51 erwise.
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53 -p socketspec
54 Specifies the socket that should be established by the filter to
55 receive connections from sendmail(8) in order to provide ser‐
56 vice. socketspec is in one of two forms: local:path which cre‐
57 ates a UNIX domain socket at the specified path, or
58 inet:port[@host] or inet6:port[@host] which creates a TCP socket
59 on the specified port within the specified protocol family. If
60 the host is not given as either a hostname or an IP address, the
61 socket will be listening on all interfaces. If neither socket
62 type is specified, local is assumed, meaning the parameter is
63 interpreted as a path at which the socket should be created. If
64 an IP address is used, it must be enclosed in square brackets.
65 This parameter is mandatory.
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67 -P pidfile
68 Specifies a file into which the filter should write its process
69 ID at startup.
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71 -t file[,file[,...]]
72 Reads email messages from the named files and processes them as
73 if they were received by the filter. The service is not
74 started, and actions normally sent back to the MTA will instead
75 be printed on standard output.
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77 -u userid[:group]
78 Attempts to be come the specified userid before starting opera‐
79 tions. The process will be assigned all of the groups and pri‐
80 mary group ID of the named userid unless an alternate group is
81 specified. See the FILE PERMISSIONS section for more informa‐
82 tion.
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84 -v Increase verbose output during test mode (see -t above). May be
85 specified more than once to request increasing amounts of out‐
86 put.
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88 -V Print the version number and supported canonicalization and sig‐
89 nature algorithms, and then exit without doing anything else.
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92 Upon receiving SIGUSR1, if the filter was started with a configuration
93 file, it will be re-read and the new values used. Note that any com‐
94 mand line overrides provided at startup time will be lost when this is
95 done. Also, the following configuration file values (and their corre‐
96 sponding command line items, if any) are not reloaded through this
97 process: AutoRestart (-A), AutoRestartCount, AutoRestartRate, Back‐
98 ground, MilterDebug, PidFile (-P), Socket (-p), UMask, UserID (-u).
99 The filter does not automatically check the configuration file for
100 changes and reload.
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103 This man page covers version 1.3.2 of opendmarc.
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106 Copyright (c) 2012, The Trusted Domain Project. All rights reserved.
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109 opendmarc.conf(5), sendmail(8)
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111 Sendmail Operations Guide
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113 RFC4408 - Sender Policy Framework
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115 RFC5321 - Simple Mail Transfer Protocol
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117 RFC5322 - Internet Messages
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119 RFC5451 - Message Header Field for Indicating Message Authentication
120 Status
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122 RFC6376 - DomainKeys Identified Mail
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124 RFC6591 - Authentication Failure Reporting Using the Abuse Reporting
125 Format
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129 The Trusted Domain Project opendmarc(8)