opendmarc(8)opendmarc(8)NAMEopendmarc - DMARC email policy filter for MTAs
SYNOPSISopendmarc [-A] [-c configfile] [-f] [-l] [-n] [-p socketspec] [-P pid‐
file] [-t file[,file[...]]] [-u userid[:group]] [-v] [-V]
DESCRIPTIONopendmarc implements the proposed DMARC specification for authentica‐
tion of message and reporting of observed traffic.
opendmarc uses the milter interface, originally distributed as part of
version 8.11 of sendmail(8), to provide a DMARC processing service for
mail transiting a milter-aware MTA.
Most, if not all, of the command line options listed below can also be
set using a configuration file. See the -c option for details.
opendmarc relies on addition of Authentication-Results fields by
upsteam filters on trusted hosts to collect input to the DMARC algo‐
rithm. It does not itself do DKIM or SPF evaluation.
OPTIONS-A Automatically re-start on failures. Use with caution; if the
filter fails instantly after it starts, this can cause a tight
fork(2) loop. This can be mitigated using some values in the
configuration file to limit restarting. See opendmarc.conf(5).
-c configfile
Read the named configuration file. See the opendmarc.conf(5)
man page for details. Values in the configuration file are
overridden when their equivalents are provided on the command
line until a configuration reload occurs. The OPERATION section
describes how reloads are triggered. The default is to read a
configuration file from /usr/local/etc/opendmarc.conf if one
exists, or otherwise to apply defaults to all values.
-f Normally opendmarc forks and exits immediately, leaving the ser‐
vice running in the background. This flag suppresses that be‐
haviour so that it runs in the foreground.
-l Log via calls to syslog(3) any interesting activity.
-n Parse the configuration file and command line arguments, report‐
ing any errors found, and then exit. The exit value will be 0
if the filter would start up without complaint, or non-zero oth‐
erwise.
-p socketspec
Specifies the socket that should be established by the filter to
receive connections from sendmail(8) in order to provide ser‐
vice. socketspec is in one of two forms: local:path which cre‐
ates a UNIX domain socket at the specified path, or
inet:port[@host] or inet6:port[@host] which creates a TCP socket
on the specified port within the specified protocol family. If
the host is not given as either a hostname or an IP address, the
socket will be listening on all interfaces. If neither socket
type is specified, local is assumed, meaning the parameter is
interpreted as a path at which the socket should be created. If
an IP address is used, it must be enclosed in square brackets.
This parameter is mandatory.
-P pidfile
Specifies a file into which the filter should write its process
ID at startup.
-t file[,file[,...]]
Reads email messages from the named files and processes them as
if they were received by the filter. The service is not
started, and actions normally sent back to the MTA will instead
be printed on standard output.
-u userid[:group]
Attempts to be come the specified userid before starting opera‐
tions. The process will be assigned all of the groups and pri‐
mary group ID of the named userid unless an alternate group is
specified. See the FILE PERMISSIONS section for more informa‐
tion.
-v Increase verbose output during test mode (see -t above). May be
specified more than once to request increasing amounts of out‐
put.
-V Print the version number and supported canonicalization and sig‐
nature algorithms, and then exit without doing anything else.
SIGNALS
Upon receiving SIGUSR1, if the filter was started with a configuration
file, it will be re-read and the new values used. Note that any com‐
mand line overrides provided at startup time will be lost when this is
done. Also, the following configuration file values (and their corre‐
sponding command line items, if any) are not reloaded through this
process: AutoRestart (-A), AutoRestartCount, AutoRestartRate, Back‐
ground, MilterDebug, PidFile (-P), Socket (-p), UMask, UserID (-u).
The filter does not automatically check the configuration file for
changes and reload.
VERSION
This man page covers version 1.3.1 of opendmarc.
COPYRIGHT
Copyright (c) 2012, The Trusted Domain Project. All rights reserved.
SEE ALSOopendmarc.conf(5), sendmail(8)
Sendmail Operations Guide
RFC4408 - Sender Policy Framework
RFC5321 - Simple Mail Transfer Protocol
RFC5322 - Internet Messages
RFC5451 - Message Header Field for Indicating Message Authentication
Status
RFC6376 - DomainKeys Identified Mail
RFC6591 - Authentication Failure Reporting Using the Abuse Reporting
Format
The Trusted Domain Project opendmarc(8)
