What is the PTR record purpose?
The PTR record also called a Pointer record, has an apparent objective. The IP address must be pointed at the domain name. Additionally, this kind of DNS record can function effectively with IPv4 and IPv6 addresses. As a result, you can configure and use Reverse DNS because of the Pointer record.
These records essentially serve as a spam filter. Spammers frequently generate fictitious domain names for their email addresses, and these names typically lack a suitable PTR record created by the DNS. Therefore, one of the fundamental criteria of many spam filters is the presence of reverse DNS. Additionally, when conducting a web and Internet traffic analysis, use a reverse DNS search to identify the service providers among your visitors.
There are no special technological requirements for PTR records. However, they are essential for some security measures due to an increase in unsolicited electronic messages (spam).
What does it look like inside (structure)?
Basically, the Pointer record is a straightforward DNS record. Below, you can see what it looks like:
Host: Here is the IP address. (IPv4 or IPv6)
Points to: The domain name.
TTL: Time-to-live value. It is not required for the TTL value of a PTR record to be low.
PTR record versus A record
We can observe that the A and PTR records are opposed. This is so because an IP address and a domain name are connected by the A record (IPv4). On the other hand, the Pointer record enables the translation of an IP address (IPv4 or IPv6) into a domain name.
The fact that the A and PTR records are situated in different DNS zones should also be noted. The PTR record can only exist, and function in a Master Reverse DNS zone, while the A record must be added to a Primary (Master) DNS zone.
Why is a PTR record necessary?
The PTR record is crucial for anyone who oversees an outgoing mail server. Although it is not necessary, it can ensure that everything goes smoothly. To avoid spam, email filtering is one of the main reasons. Many mail servers employ Pointer records to block messages from IP addresses that lack rDNS or are unlikely to be accurate, which helps to reduce spam. Without reverse DNS, your emails may likely land in the spam folder of your intended recipients. Because of this, creating PTR records is crucial.
Let’s recap. PTR is a DNS record type that connects an IP address to a domain. Since the record only points from one to the other, PTR stands for “pointer.” It demonstrates your dependability on external mail servers and, in many situations, keeps your outgoing mail from being refused or blocked. It’s worth implementing!