To protect customers from unsolicited email, many ISPs check the domain key used in an email message to determine whether it is spam or not. DomainKeys Identified Mail (DKIM) is a method of digitally signing your email messages to allow authentication.
When sending email from your NetSuite production account, using your own domain key increases campaign delivery rates and helps enhance your reputation as a legitimate marketer. Without DKIM, you cannot send more than 10,000 messages in a single email campaign.
When set up, your domain keys will be used to authenticate all email messages sent from NetSuite.