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Bear in mind that this documentation is for the last available version. If you use an older version, you must refer to the README.md file inside the plugin archive.
i-MSCP OpenDKIM plugin
Provides DomainKeys Identified Mail (DKIM) service through MILTER.
Introduction
DKIM provides a way for senders to confirm their identity when sending email by adding a cryptographic signature to the headers of the message.
Requirements
- i-MSCP Serie ≥ 1.4.x
Installation
- Upload the plugin through the plugin management interface
- Install the plugin through the plugin management interface
Update
- Be sure that all requirements as stated in the requirements section are met
- Backup your plugin configuration file if needed
- Upload the plugin through the plugin management interface
Restore you plugin configuration file if needed
- Restore your plugin configuration file (compare it with the new version first)
- Update the plugin list through the plugin management interface
Configuration
When changing a configuration parameter in the plugin configuration file, don't forget to trigger a plugin list update, else you're changes will not be token into account.
Plugin working level
It is possible to choose the plugin working level through the
plugin_working_level plugin configuration parameter. There are actually two
working levels which are admin and reseller.
When it works at the admin level, the plugin activates OpenDKIM for all
customers automatically. In this working level, resellers can only trigger
renewal of DKIM keys through their own management interface.
When it works at reseller level, the plugin doesn't activate OpenDKIM
automatically for customers. Resellers must enable the OpenDKIM feature
manually for all of their customers.
Usage of an external DNS server
If you make use of an external DNS server (not the one managed by i-MSCP), you must not forget to add the DKIM and ADSP DNS resource records in the zone of your domain.
Each domain has one DKIM and one ADSP DNS resource records and each subdomain has one ADSP resource record.
Testing
Internal DKIM test
You can check on the command line if OpenDKIM is working for your domain by running the following command:
opendkim-testkey -d example.com -s mail -vvv
The result should look similar like this one:
root@jessie32:/etc/opendkim# opendkim-testkey -d weird.test.bbox.nuxwin.com -s mail -vvv
opendkim-testkey: using default configfile /etc/opendkim.conf
opendkim-testkey: checking key 'mail._domainkey.weird.test.bbox.nuxwin.com'
opendkim-testkey: key not secure
opendkim-testkey: key OK
Note that the key not secure message doesn't indicate an error. It is the
expected consequence of not using DNSSSEC.
You can also query your DNS server to check the TXT record for your domain:
dig -t txt mail._domainkey.example.com
External DKIM test
Go to dkimvalidator.com and send a mail from the
domain for which you activated OpenDKIM to the random mail address. Once you
have sent the mail, wait few seconds and then, click on the View Results
button. You should get a result similar to:
Original Message
Received: from jessie32.bbox.nuxwin.com (xxx-xxx-xx-xx.abo.bbox.fr [xxx.xxx.xx.xx])
by relay-4.us-west-2.relay-prod (Postfix) with ESMTPS id 9B57F160208
for <[email protected]>; Sat, 2 Sep 2017 18:29:48 +0000 (UTC)
Received: from panel.bbox.nuxwin.com (jessie32.bbox.nuxwin.com.local [127.0.0.1])
(Authenticated sender: [email protected])
by jessie32.bbox.nuxwin.com (Postfix) with ESMTPA id F3E645FC6A
for <[email protected]>; Sat, 2 Sep 2017 20:30:21 +0200 (CEST)
DKIM-Filter: OpenDKIM Filter v2.9.2 jessie32.bbox.nuxwin.com F3E645FC6A
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple;
d=weird.test.bbox.nuxwin.com; s=mail; t=1504377022;
[email protected];
bh=g3zLYH4xKxcPrHOD18z9YfpQcnk/GaJedfustWU5uGs=;
h=Date:From:To:Subject:From;
b=HdAyJ/C0tBH5UkzZSGXo2ESZ6+8tCr1O/LC3REVuyRg1TSB/bYGDAv/H05+nJSisD
fExsy/Irnjjz5bVNSUq0nB8mPoHaTMibh9mWAC/Q23WDsu9j9vprH5TGw0k91UUuur
XQm2anEaugJtvEpCSdOf3CMHlxUF9M/oMti+Bm0N/aoqsvu1vRZHazQH4PUMd+Thyq
PtnEx4ZPQaU/f1HOdZTi7c4KjwWHoLDdQ1mNAwknUMjm5hsw2MGIIW0ecumNqzzKZH
vIFhX75q2Hw03rByI5paaUrf6bAEozOmQghDTzz+07pn/aYhoK+jNYMEvev/F8pRqz
596UbuEZYMC1w==
MIME-Version: 1.0
Content-Type: text/plain; charset=US-ASCII;
format=flowed
Content-Transfer-Encoding: 7bit
Date: Sat, 02 Sep 2017 20:30:21 +0200
From: [email protected]
To: [email protected]
Subject: test
Message-ID: <[email protected]>
X-Sender: [email protected]
User-Agent: Roundcube Webmail/1.2.5
test
DKIM Information
DKIM Signature
Message contains this DKIM Signature:
DKIM-Filter: OpenDKIM Filter v2.9.2 jessie32.bbox.nuxwin.com F3E645FC6A
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple;
d=weird.test.bbox.nuxwin.com; s=mail; t=1504377022;
[email protected];
bh=g3zLYH4xKxcPrHOD18z9YfpQcnk/GaJedfustWU5uGs=;
h=Date:From:To:Subject:From;
b=HdAyJ/C0tBH5UkzZSGXo2ESZ6+8tCr1O/LC3REVuyRg1TSB/bYGDAv/H05+nJSisD
fExsy/Irnjjz5bVNSUq0nB8mPoHaTMibh9mWAC/Q23WDsu9j9vprH5TGw0k91UUuur
XQm2anEaugJtvEpCSdOf3CMHlxUF9M/oMti+Bm0N/aoqsvu1vRZHazQH4PUMd+Thyq
PtnEx4ZPQaU/f1HOdZTi7c4KjwWHoLDdQ1mNAwknUMjm5hsw2MGIIW0ecumNqzzKZH
vIFhX75q2Hw03rByI5paaUrf6bAEozOmQghDTzz+07pn/aYhoK+jNYMEvev/F8pRqz
596UbuEZYMC1w==
Signature Information:
v= Version: 1
a= Algorithm: rsa-sha256
c= Method: relaxed/simple
d= Domain: weird.test.bbox.nuxwin.com
s= Selector: mail
q= Protocol:
bh= g3zLYH4xKxcPrHOD18z9YfpQcnk/GaJedfustWU5uGs=
h= Signed Headers: Date:From:To:Subject:From
b= Data: HdAyJ/C0tBH5UkzZSGXo2ESZ6+8tCr1O/LC3REVuyRg1TSB/bYGDAv/H05+nJSisD
fExsy/Irnjjz5bVNSUq0nB8mPoHaTMibh9mWAC/Q23WDsu9j9vprH5TGw0k91UUuur
XQm2anEaugJtvEpCSdOf3CMHlxUF9M/oMti+Bm0N/aoqsvu1vRZHazQH4PUMd+Thyq
PtnEx4ZPQaU/f1HOdZTi7c4KjwWHoLDdQ1mNAwknUMjm5hsw2MGIIW0ecumNqzzKZH
vIFhX75q2Hw03rByI5paaUrf6bAEozOmQghDTzz+07pn/aYhoK+jNYMEvev/F8pRqz
596UbuEZYMC1w==
Public Key DNS Lookup
Building DNS Query for mail._domainkey.weird.test.bbox.nuxwin.com
Retrieved this publickey from DNS: v=DKIM1; h=sha256; k=rsa; s=email; p=MIIBIjANBgkqhkiG9w0BAQEFAAOCAQ8AMIIBCgKCAQEAsGfEnQP49L7DrUvR8/cPOciHvATQkxXTgBm4qUcNFFDLnT6s45xsmU068RTED/QGJWaeL2eQcd7c5p7dlUdqVugYSfB+aDjOJuvPIr3P/jiISt6HERoBafu7pkc2mj92S70Xq3Jyx6lgIhMe63UGKyeyuBJHB7Nm3KHHiZFqH7AWtQwgBpMqa7LKPj4OCIELZ+G8SO8OMAkytLndDf40lABXXHsyjFSTaOPb27BStTLBmZT58AwPtSHTZ7+8hz+reHZDUXMos96SiwcvxOepDMSBMMdKpAI7iu+v86F+ewaMRllAogVIAFZb68DgjAUvk6fwDE4mwGyGk1y7QdKVEwIDAQAB
Validating Signature
result = pass
Details:
SPF Information
Using this information that I obtained from the headers
Helo Address = jessie32.bbox.nuxwin.com
From Address = [email protected]
From IP = xxx.xxx.xx.xx
SPF Record Lookup
Looking up TXT SPF record for sub1.weird.test.bbox.nuxwin.com
Found the following namesevers for sub1.weird.test.bbox.nuxwin.com:
Retrieved this SPF Record: zone updated 20170902 (TTL = 43897)
Using local nameserver for SPF resolution. This will probably be cached!
Result: pass (Mechanism 'include:weird.test.bbox.nuxwin.com' matched)
Result code: pass
Local Explanation: sub1.weird.test.bbox.nuxwin.com: Sender is authorized to use '[email protected]' in 'mfrom' identity (mechanism 'include:weird.test.bbox.nuxwin.com' matched)
spf_header = Received-SPF: pass (sub1.weird.test.bbox.nuxwin.com: Sender is authorized to use '[email protected]' in 'mfrom' identity (mechanism 'include:weird.test.bbox.nuxwin.com' matched)) receiver=dkimvalidator.com; identity=mailfrom; envelope-from="[email protected]"; helo=jessie32.bbox.nuxwin.com; client-ip=xxx.xxx.xx.xx
Regarding the SpamAssassin information at bottom, you can ignore them as the SpamAssassin installation used is not able to validate DKIM signatures when DKIM ADSP extension is involved.
License
i-MSCP OpenDKIM plugin
Copyright (C) 2013-2017 Laurent Declercq <[email protected]>
Copyright (C) 2013-2016 Rene Schuster <[email protected]>
Copyright (C) 2013-2016 Sascha Bay <[email protected]>
This program is free software; you can redistribute it and/or modify
it under the terms of the GNU General Public License as published by
the Free Software Foundation; version 2 of the License
This program is distributed in the hope that it will be useful,
but WITHOUT ANY WARRANTY; without even the implied warranty of
MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
GNU General Public License for more details.
