DKIM (DomainKeys Identified Mail) is an authentication protocol that uses cryptographic signatures to ensure that email messages are not tampered with during transit and truly originate from your domain.
This guide outlines how to configure DKIM for Trend Micro Email Security, a cloud-based solution that filters and secures inbound and outbound email communications.
Log in to your Trend Micro Email Security console.
Navigate to:
Outbound Protection → DomainKeys Identified Mail (DKIM) Signing
Click Add to open the Add DKIM Signing Settings screen.
From the Managed Domain dropdown, select the specific sender domain you want to configure.
Check the box to Enable DKIM signing.
(Optional) Check Sign email messages with no envelope sender addresses.
This allows Trend Micro to apply DKIM signing even to system-generated messages (like bounces or auto-replies) by using the “From” header as the domain reference.
Configure the following DKIM general settings:
SDID (Signing Domain Identifier): Select the domain you want to use for signing.
Selector: Retain the default selector unless you need to customize it.
Headers to sign: Choose the headers to be included in the DKIM signature. You can select multiple or customize as needed.
Wait time: Specify how long to wait before the key becomes active. This time begins once the public key is detected in DNS.
Key pair: Choose the key length (1024 or 2048 bits), then click Generate to create the DKIM key pair.
Publish the public key in your DNS or Sendmarc, if you’re using our DKIM management feature.
Save your settings to complete DKIM setup.
To update your DKIM record through Sendmarc, please refer to the Sendmarc DKIM Setup Documentation.
Trend Micro Email Security’s official DKIM configuration guide can be found here.
Find out how to configure your Trend Micro Email Security SPF settings here.