What is a PTR record?
A PTR record maps an IP address back to a hostname, the reverse of an A record. It lives in the in-addr.arpa zone and is set by whoever controls the IP, usually your hosting or sending provider. Receivers look for one on every sending IP and check that the hostname resolves back to the same address.
Reading the result
Enter an IPv4 address. You get the hostname its PTR record returns and whether that hostname resolves forward to the same IP, which is called forward-confirmed reverse DNS (FCrDNS). Confirmed is what receivers want. Mismatch means the hostname points somewhere else, and missing means there is no PTR record at all.
Beat runs on the same engine, on a schedule, across all 41 checks and 25 blacklists. What it adds is asking again, noticing when an answer changes and telling you what to do about it.
Common reverse DNS problems
No PTR record
Gmail requires sending IPs to have valid forward and reverse DNS, and some blacklists, SpamRats NoPTR among them, list IPs without one. The record sits in the IP owner's zone, so ask your provider to set it.
Forward and reverse disagree
The PTR hostname has to resolve back to the sending IP. When it points elsewhere, receivers treat the reverse DNS as unverified.
A generic hostname
Names built from the IP itself, like ip-203-0-113-7.provider.net, look like consumer connections to some filters. A hostname under your own domain reads as a deliberate mail server.