Question
Why should I remove legacy DNS entries?
Answer
Previously, Zendesk recommended adding the four cname records below. We now recommend that you remove these legacy DNS entries. Only legacy customers will have them. While these records will cause no harm, it's best practice to remove non-functional records of any kind.
zendesk1.yourdomain.com >> mail1.zendesk.com zendesk2.yourdomain.com >> mail2.zendesk.com zendesk3.yourdomain.com >> mail3.zendesk.com zendesk4.yourdomain.com >> mail4.zendesk.com
For more information, see this article: Allowing Zendesk to send email on behalf of your email domain.