DKIM : DomainKeys Identified Mail

What's DKIM? Before starting How does it work? Generate your public and private keys Add your DNS record DirectAdmin OVH GoDaddy Check your DNS record Make sure your e-mails are signed

What's DKIM?

DKIM is a method enabling your receivers to make sure the message they received is coming from your own domain name.

DomainKeys Identified Mail on Wikipedia

Before starting

Since AcyMailing 1.7.0, we propose in our commercial versions a way to sign your messages using DKIM (AcyMailing will add a DKIM signature to each message).

If your mail server already handles a DKIM signature or if there is a way to enable this DKIM signature on your server without using the AcyMailing one, then you should NOT use the AcyMailing DKIM signature but configure the one you have on your server.

Cpanel, Plesk, Sendmail, Postfix, QMail will enable you to handle a DKIM signature automatically.

The same way, if you already use an SMTP server which handles DKIM, you should not enable the AcyMailing DKIM signature.

How does it work?

First of all, you will have to generate a public key and a private key.

The private key will be then added to AcyMailing and the public key will be added to your DNS records.

When you send an e-mail, AcyMailing will encode the message using the private key which can be decoded using the public key (publicly visible on your DNS).

Generate your public and private keys

Do not generate your keys twice!
Please make sure to use the public key matching with your private key. You can not use a public key from a first generation and then a private key from an other generation, it won't work and you will have the error message "fail (signature doesn't verify)" when you test DKIM.

Please enter your domain name (example: google.com) and a selector (you can keep the default one: acy)
then click on the button "Generate Keys" to generate your public and private keys.

Please generate your keys and save the result on your AcyMailing configuration page.
Do not alter the generated keys and simply copy/paste it in the AcyMailing configuration without modification.
Acyba.com does not save your keys and if you refresh the page, an other key will be generated.

The above form is not a screenshot, you won't see it on your AcyMailing configuration page, you should really use it to generate your keys!

Copy each result on the appropriate field on the AcyMailing configuration page.

• Domain: It should be your own domain name. Do not add http:// or www. in front of it.
• Selector: Your DNS can handle multiple records for DKIM. The selector is there to identify the one you are using. We recommend you to keep "acy".
• Private key: Please copy your private key in this area.
• Passphrase: If you generated your keys on an other website, you may have to use a passphrase in which case you should fill this field properly.
  If you generated your keys on our own website, you don't need any passphrase.
• Identity: This parameter can enable you to restrict the allowed e-mail addresses. Please leave this field empty.
• Public Key: AcyMailing won't use this field, it has been added for ease of use and as a reminder ; you can store the DNS Record directly or your public key in it.

Add your DNS record

You should now add the generated DNS record on your own DNS via your hosting company interface.

Don't forget to increment the number of your DNS zone and to make sure the changes are applied.

If you don't know how to do that, please ask your hosting company to add the provided DNS record.

You may be able to access this kind of interface in which case you should fill each field separately:

Add your DKIM DNS entry on directadmin

• On DirectAdmin, you should insert your DNS entry on the "TXT" line and then click on the button "Add".

Add your DKIM DNS entry on OVH

You should not use the "add a DKIM entry" interface on OVH but rather add a simple TXT entry:

• Click on "Domain & DNS" then "Zone DNS"

• Add a record "Type TXT"

• Enter the generated entry

Add your DKIM DNS entry on GoDaddy

• Login to your GoDaddy Control Panel, select your domain and access your Settings -> DNS Manager
• Scroll down to the TXT (Text) area of your DNS and add a new key with
  • Host : acy._domainkey
  • TXT Value : v=DKIM;k=rsa;g=*;s=email...
• Then click on the button "Save Zone File" to apply your newly created entry

Check your DNS record

Before even trying to send an e-mail, you should make sure your DNS record has been added properly to your website.

Please use BOTH tools to check it:

• http://www.sendmail.org/dkim/checker

This is an example of a valid DKIM record checked on the sendmail.org website.
If your DKIM record is not set properly, you won't see the Key type / Service / Granularity information but you will only see a message "No problems to report!" which indicates that... there is a problem!

 

 

• http://dkimcore.org/tools/keycheck.html

The DKIM Core verification will indicate you're using sha1 and you should rather use sha256. We are aware of it and will probably provide a sha256 support in the future.

Make sure your e-mails are signed

If both services return a success status and you saved your AcyMailing configuration with the DKIM parameters, then your e-mails will be automatically signed!

You can test it by sending an e-mail (from AcyMailing) to check-auth2@verifier.port25.com.

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