DNS problems affecting e-mail delivery: PTR records
PTR Record - Confluence This example shows how to overwrite an existing PTR record with a new IP address, 184.108.40.206. header-ptrrecord,dname*,address ptrrecord,ptr.corp100.com,220.127.116.11. Merging PTR Record Data. This example shows how to change the DNAME of a PTR record from ptr.corp100.com to ptr2.corp100.com, and to add comment = East Asia. How to setup Reverse DNS and PTR records | Computerworld DNS can be tricky. There is a lot to know and, even when you think you have a firm grasp on it, surprises still pop up. Reverse DNS and PTR record configuration is one of those sneaky topics, but PTR record | Explanation, Check/Lookup & Example - IONOS
The PTR record is used in reverse-lookup zones for reverse DNS searches. Example of an PTR record: example.com record type: value: TTL @ PTR: example.com: 71200: The value here represents an email address ,which can be confusing because it’s missing the ‘@’ sign, but in an SOA record admin.example.com is the equivalent of firstname.lastname@example.org.
A pointer (PTR) record is a type of Domain Name System (DNS) record that resolves an IP address to a domain or host name, unlike an A record which points a domain name to an IP address. PTR records are used for the reverse DNS lookup. Using the IP address, you can get the associated domain or host name. An A record should exist for every PTR Record types other than PTR records may also appear in the reverse DNS tree. For example, encryption keys may be placed there for IPsec , SSH and IKE . DNS-Based Service Discovery uses specially-named records in the reverse DNS tree to provide hints to clients about subnet-specific service discovery domains. 
Oct 28, 2019
Feb 14, 2018 Pointer (PTR) Record – Network Encyclopedia