OpenDKIM with Postfix on CentOS 6.4
DKIM is the mail service to sign and verify email using public/priviae keys and use DNS server to supply public key data to recipient MTA. OpenDKIM is the package name to be able to implement DKIM service on Linux system. I hope that you will understand the concept of DKIM and how to implement DKIM service with Postfix from this video tutorial.