How to configure a PTR record in Plesk?
To add a new resource record to the zone:
Go to the Domains > example.com > DNS Settings
Click Add Record .
Select record type as PTR , and specify the appropriate data.
Click OK, and then click Update.
Note: Plesk UI supports creating PTR records with the following subnet masks: 8, 16, 24.
General documentation about DNS management in Plesk can be found in Plesk Administrators Guide .
For more details on PTR records and it's format check the following link http://help.dnsmadeeasy.com/managed-dns/dns-record-types/ptr-record/