Table of Contents

Adding DKIM for New Domain

Problem

When sending emails from a new domain on existing server, you get DKIM Unaligned because the domain is not configured in OpenDKIM.

Solution Steps

1. Add to KeyTable

echo "default._domainkey.domain.com domain.com:default:/etc/opendkim/keys/domain.com/default.private" >> /etc/opendkim/KeyTable

2. Add to SigningTable

echo "*@domain.com default._domainkey.domain.com" >> /etc/opendkim/SigningTable

3. Generate DKIM Keys

mkdir -p /etc/opendkim/keys/domain.com
opendkim-genkey -D /etc/opendkim/keys/domain.com -d domain.com -s default
chown -R opendkim:opendkim /etc/opendkim/keys/domain.com

4. Add to TrustedHosts

echo "domain.com" >> /etc/opendkim/TrustedHosts

5. Restart OpenDKIM

systemctl restart opendkim

6. Update DNS

Get the public key: 

cat /etc/opendkim/keys/domain.com/default.txt

Add the TXT record to your DNS zone: 

default._domainkey.domain.com.    IN    TXT    "v=DKIM1; k=rsa; p=YOUR_PUBLIC_KEY_HERE"

Result

Emails from domain.com will now show DKIM Aligned ✓