PTR (pointer) records are essentially the reverse of an A record. PTRs map an IP address to a host name. Certain tools, when given an IP address, will attempt to resolve that IP address into a host name to give a clearer understanding of network paths and actual end point connections. PTR records are most often used in mail transactions as an anti-spam technique.
When setting up a PTR record it is important to understand that these are unrelated to forward lookup zones. The ISP that you lease your IP block from is the authority for this reverse zone. In most cases a simple call to the ISP to request the appropriate PTR record is the correct action. Though sometimes the ISP will delegate control of the reverse DNS zone and it will need to be configured on the Ecessa device. If the reverse zone for your IP block has been delegated to you then follow the directions below.
The following is an example Simple Host (A) Record:
A PTR record for the above A record in the standard format would be the following. Note that there are other formats that may be used in the Domain Name field.