Method to correct DKIM signatures, not valid errors

DKIM, or Domain Key, is a protocol that helps identify an authenticated email.

The recipient server can easily authenticate the mail with a DKIM signature header.

It helps to maintain the facts of the content of the email message by making changes not made during the transfer. It helps to prevent your message from middle attackers from changing the content.

Reasons for the DKIM error:

While checking the DKIM signature, sometimes there is a possibility to show results as “DKIM signature not valid.” Some of the reasons for not validating the signature or the DKIM error.

The domains of the DKIM signature and sender do not align properly.

• There is a possibility that the DKIM public key record of DNS published was wrong.
• Maybe the DKIM public key record list to be published in DNS is not listed or not published.
• May the server fail to reach the DNS zone of the sender for a lookup. It is the most common condition of DKIM error faced by poor or bad host providers.
• Not sufficient length of the DKIM key leads to error. Mostly, they supported keys with 1024-bit or 2048-bit keys.
• When the host provider signs a key with a shorter length, an invalid DKIM signature occurs.
• Modifications made during the forwarding of the message lead to an error.

From above, all the issues other than the last one are technical. Which needs an expert to resolve the issue. The previous issue is somewhat difficult or not possible to control because one can’t force the recipients to stop appending.

In earlier days, it was challenging for recipient servers to manage legitimate emails that were unauthenticated. But now, the ARC  (Authenticated Received Chain) protocol is used by email service providers or ESPs.

The ARC protocol helps the service provider identify the server that they managed previously. These help or let them know about the authentication assessment test.

To know the DKIM error:

Open Powered Dmarc and choose the DKIM lookup tool.

You need to enter the domain name and selector to find an error. If you don’t know the selector, leave it blank, and the tool can detect your sector automatically.

Then the tool will analyze the DKIM entry and show or highlight the syntax.

Fix the errors:

• Open any DNS management console or cPanel that you use.
• Choose the Advance DNS Zone Editor option, which comes under Domain.
• Choose a domain from the record.
• Navigate to edit the DNS record.
• Type the correct value by changing the current value in the DNS record.