Part 4: Set Up SPF and DKIM with Postfix on CentOS/RHEL Mail Server

After completing part 1 and part 2, we have a working Postfix SMTP server and Dovecot IMAP server. We can send and receive email using a desktop email client. Although I have created correct MX, A and PTR record, my emails were flagged as spam by Gmail and Outlook mail. So in this part, we are going to look at how to improve email delivery to recipient’s inbox by setting up SPF and DKIM on CentOS/RHEL server.

What are SPF and DKIM Records?

SPF and DKIM are two types of TXT records in DNS that can help with preventing email spoofing and making legitimate emails delivered into the recipient’s inbox instead of spam folder. If your domain is abused by email spoofing, then your emails are likely to landed in recipient’s spam folder if the recipient didn’t add you in address book.

Read full tutorial here: https://www.linuxbabe.com/redhat/set-up-spf-dkim-postfix-centos