Definitions for "Reverse DNS Lookup"
Keywords:  lookup, dns, hostname, trimmail, rdns
DNS is used to determine what IP address is associated with a given hostname. This process is using a known IP address is to lookup what the associated the hostname/domain for it is.
a query to the domain name system (DNS) that returns a domain name for an IP address
Use the sender's Internet Protocol address listed in the message header to query a Domain Name Server to make sure the sender's domain matches the sending domain listed in the message header. trimMail Inbox performs a reverse DNS lookup, and adds results to its message score.