DKIM Signature

The DKIM signature (DomainKeys Identified Mail) is an email authentication method that recognizes the actual identity of the domain that is sending messages and helps prevent spoofing activities on outgoing messages. All messages sent by Qboxmail SMTP are automatically signed with a shared DKIM digital signature, in order to increase their reputation and ensure greater security. Qboxmail also offers the possibility to set a personalized DKIM signature for each domain.

Custom DKIM signature: what is it?

A custom DKIM signature can be useful for isolating the reputation of one's domain from that of others using a shared signature. Moreover, having a custom signature is also a requirement to activate specific services such as DMARC (Domain-based, Message Authentication Reporting and Compliance), a useful tool to combat email spoofing.

Add a custom DKIM signature

To add a custom DKIM signature, find the Domain entry in the control panel sidebar. Then, select the domain name that you want to set the DKIM signature for and select the Settings item from on the tab. Go to the Security domain settings and enter the Custom DKIM Signature section. Click on the Activate DKIM button, then follow the wizard to create the signature.

  • Domains > Domain name > Settings > Security > Custom DKIM signature > Enable DKIM

Step 1: Generate a DKIM signature

  1. Click on the Activate DKIM button and generate the selector and public key of your DKIM signature.

The selector is the first part (ex. Qbm1807252189._domainkey), while the public key is the part starting with v = DKIM1; k = rsa; p = MIGFMA ...

Step 2: Change the DNS parameters of your domain

  1. Connect to the DNS management panel of your domain;
  2. Enter the selector as a TXT type record in the subdomain field (the name may vary depending on the type of DNS panel);
  3. Enter the public key in its entire length, as a TXT record, in the value field.

The process of activation of a newly entered record may take up to 24 hours.

Step 3: Verify the DNS of the signature

  1. Open the security settings of the domain that you wish to activate the custom signature for and click on the Custom DKIM signature section. Then, click on the Check DKIM configuration button.

The system will immediately check the records entered in the DNS. In case of a positive response, your personalized DKIM signature will be active within a few minutes. Therefore, all messages sent via Qboxmail SMTP from any of the email addresses linked to your domain will contain your custom digital signature.

If the verification procedure is not successful, check that the DNS settings are correct. If the problem persists for more than 24 hours, contact our technical support. An unverified DKIM signature is automatically removed from the system after 7 days.

If the TXT records located in the DNS of the domain and related to the DKIM signature are removed, our SMTP will continue to sign the emails but the signatures will not be verifiable.

If you need to remove the TXT records from the DNS, you will also need to remove the custom DKIM signature from the Qboxmail control panel.

Check the DKIM signature via Tracemail

Tracemail, the system that allows you to analyze email traffic logs in real time, can verify that the personalized DKIM signature is correctly applied to your domain. Moreover, the system allows you to verify that the shared signature is still present.

To view which DKIM signature is applied to messages, follow this procedure:

  1. Find the Tracemail entry in the control panel sidebar;
  2. Select Mail Sent;
  3. Enter the name of the domain whose logs you want to view;
  4. Enter the name of the email account whose log you want to view.

Finally, click on Search and the results will appear. By clicking on Show details next to each sent email, you will be able to view the details of the DKIM domain and selector applied to that specific sent email:

  • DKIM selector
  • DKIM domain

Delete a custom DKIM signature

To delete a custom DKIM signature, click on the Domain entry in the control panel sidebar and select the domain name that you set the signature for. Then, go to the Settings > Domain Settings > Security > Custom DKIM Signature. Here. click on the Disable DKIM button.

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