PTR Record

Pointer Records, or PTR Records, are used to map a network interface (IP) to a host name. These are primarily used for Reverse DNS. For example:

Domain Name: 1.168.192.in-addr.arpa
This value is delegated to you by your ISP, or whoever owns the IP address of your domain.

Name: 25
Generally the last octet of your IP, which in a PTR record is appended to the beginning of the domain.

Data (PTR to):
dnsuniversity.com
The domain name that the IP is being mapped to.

Result: This will create a reverse DNS entry for 192.168.1.25. The reverse DNS will be a pointer to dnsuniversity.com.