What Is DKIM (DomainKeys Identified Mail)? Print

Overview

DKIM (DomainKeys Identified Mail) is an email authentication method that helps protect email messages from being altered or forged during transmission. It works by attaching a digital signature to outgoing emails, allowing receiving mail servers to verify that the message was sent by an authorized domain and has not been modified.

DKIM uses public and private key encryption and is widely supported by major email providers.

Why Is DKIM Important?

DKIM provides several key benefits:

• Prevents email tampering and spoofing

• Improves email deliverability

• Reduces the likelihood of emails being marked as spam

• Protects your domain’s reputation

• Works alongside SPF and DMARC for stronger email security

Many mail providers rely on DKIM validation when deciding whether to accept or trust an email.

How DKIM Works

1. An outgoing email is digitally signed by the sending mail server using a private key

2. The public key is published in the domain’s DNS as a TXT record

3. The receiving mail server retrieves the public key from DNS

4. The digital signature is verified to confirm message authenticity and integrity

If verification succeeds, the email passes DKIM checks.

What Does a DKIM Record Look Like?

A DKIM record is added as a TXT record in DNS.
Example:

Explanation:

• default – DKIM selector

• _domainkey – DKIM namespace

• v=DKIM1 – DKIM version

• k=rsa – Encryption method

• p= – Public key

Common DKIM Issues

• DKIM record missing from DNS

• Incorrect selector name

• Truncated or invalid public key

• DKIM disabled on the mail server

• DNS propagation delays

These issues may cause email authentication failures or reduced deliverability.

How to Enable or Add DKIM

1. Log in to your hosting control panel (e.g. cPanel)

2. Navigate to Email Deliverability

3. Enable DKIM for the domain

4. Ensure the DKIM TXT record is published in DNS

5. Allow time for DNS propagation (up to 24 hours)