PhoenixDKIM

This page documents PhoenixDKIM, a maintained fork of OpenDKIM. Options may differ from the original.

NAME

opendkim-testmsg - DKIM message test tool

SYNOPSIS

opendkim-testmsg [-C] [-d domain] [-K] [-k keypath] [-s selector] [-t path]

DESCRIPTION

opendkim-testmsg signs or verifies an input message. This is similar to the test mode for except that it does not use the same configuration system or milter interface. Rather, it is a direct access to the DKIM library with those functions out of the way.

The message is read from standard input. In signing mode, the complete signed message will then be written to standard output. When verifying, there will be no output unless an error occurred.

To sign a message, the -d, -k and -s options must all be provided. If all of them are absent, the input message will be verified. If some but not all are present, an error is returned.

Both RSA and Ed25519 private keys are supported.

OPTIONS

-C
If specified, the signature header field generated in signing mode will be line-terminated with carriage-return line-feed, instead of just line-feed.
-d domain
Names the domain in which signing is to be done. More specifically, names the domain in which the public key matching the provided private key would be found in a live test.
-K
Arranges to keep temporary files generated during message canonicalization for debugging purposes.
-k keypath
Specifies the path to the private key file which should be used to sign the input message.
-s selector
Names the selector within the specified domain that should be included in the signature.
-t path
Specifies the directory in which temporary files are to be created. The default is /tmp.

VERSION

This man page covers the version of opendkim-testmsg that shipped with version 3.0 of OpenDKIM.

COPYRIGHT

Copyright (c) 2009-2015, The Trusted Domain Project.
Copyright (c) 2026, PhoenixDKIM contributors.
All rights reserved.

SEE ALSO

RFC 6376 - DomainKeys Identified Mail

RFC 8463 - A New Cryptographic Signature Method for DomainKeys Identified Mail (Ed25519)

This document was created by using the manual pages.
Time: 10:39:48 GMT, May 22, 2026