Gammadyne Corporation

DKIM for Gammadyne Mailer

DKIM is a technology that allows the recipient of an email to verify that the email came from the person who claims to have sent it, and was not a forgery.  This is achieved by inserting a digital signature as an email header.  It also offers a small benefit to successful email deliverability.

When To Use

If you have your own mail server that you relay emails through, it is generally better to configure DKIM on the mail server.  That way, it will sign all outgoing emails, and you will not need to configure anything in Gammadyne Mailer.  The instructions for how to do this in cPanel are here.  It's possible your mail server is already doing this.  We recommend using the Single Send tool (on the Tools menu) to send yourself an email.  If the test email arrives with a DKIM-Signature: header, you can stop now.

If you are using Direct Delivery, or if you can't configure the relaying SMTP server to use DKIM, then you can configure Gammadyne Mailer to sign the emails.  But first be aware that you must have access to DNS records.  If you are sending emails from newsletter@example.com then you will need to be able to add a new DNS record to the example.com server.

Procedure

The following procedure will configure Gammadyne Mailer to sign all outgoing emails with DKIM:
  1. Open or create the project that you use to send an email campaign.
  2. Go to the Send/Security branch.  Check the "Sign With DKIM" box.
  3. In the "Domain" field, enter the domain name of your website (e.g. "example.com").
  4. In the "Selector" field, enter a name for this DKIM key pair.  The Selector can be anything you wish, such as "default".  Some companies might want to assign a different key for each department for example.
    Gammadyne Mailer DKIM Setup Screenshot #3
  5. Click the "Generate" button.  The Generate Window will appear.  It will contain a newly generated random key pair, and the information you need to create the DNS record.
    Gammadyne Mailer DKIM Setup Screenshot #3
  6. Go to your web server's DNS server management tool.  Create a new subdomain named "_domainkey".
    Gammadyne Mailer DKIM Setup Screenshot #3
  7. Under the "_domainkey" subdomain, create a new TXT record.  The record name must be identical to the "Selector" field.  The record value must be identical to the "DNS Record Value" field (as shown on the Generate Window).
  8. Click "OK" to close the Generate window.  The private key will be copied into the project.
  9. Click the "Test" button.  If there is a problem, the DNS record is probably not correct.  You can test the DNS record here.

Notes

  • The public and private keys are a matched pair.  You cannot open the Generate window and use just one of its keys.
  • Some SMTP relays (like Gmail) will sign all outgoing email with DKIM.  Therefore you do not need to configure Gammadyne Mailer to do it.
  • To test DKIM, or to determine if your relay is already using it, launch the Simple Send tool (from the Tools menu) and send an email to check-auth2@verifier.port25.com