Reverse DNS
Also known as: rDNS, FCrDNS
Reverse DNS is the process of resolving an IP address back to a domain name, the opposite of standard DNS lookup.
Reverse DNS (rDNS) allows a server to verify who is calling it. While standard DNS maps a domain name (like bento.com) to an IP address, Reverse DNS maps an IP address back to a hostname.
Email providers like Gmail and Outlook use rDNS to verify that the server sending an email is actually authorized to send mail for that domain. If the rDNS lookup fails or doesn't match the "forward" DNS record (a check called "Forward-Confirmed reverse DNS" or FCrDNS), the email is often rejected or marked as spam.
Having a valid rDNS record (via a PTR record) is a mandatory requirement for any dedicated IP sending marketing email today.
Related Terms
PTR Record(Pointer record)
A PTR record is a type of DNS record that maps an IP address to a domain name, used for Reverse DNS.
Learn more →Domain Reputation
How trusted your sending domain is by email providers like Gmail and Outlook. A strong domain reputation keeps your emails in the inbox instead of spam.
Learn more →From Address(From Field)
The email address people see as the sender in their inbox. It tells them who the message is from and helps them decide whether to open it.
Learn more →Authentication
The process of proving to inbox providers that your emails really come from your domain. It helps stop spoofing and keeps more of your messages out of spam.
Learn more →