A DNS Pointer Record (PTR Record) is a type of DNS record stored in a DNS file. It acts as a "pointer" and associates a domain name with a given IP address. Simply put, it is the exact opposite of an "A" record, which provides the IP address associated with a domain name.
A PTR record is used to perform a reverse DNS lookup. A reverse DNS lookup will try to look up the domain name associated with a given IP address (opposite of a forward DNS lookup). PTR records are mainly used in email services.
For example, when you receive an email, the email client will perform a reverse DNS lookup using the PTR record to determine its validity. If the lookup returns a valid domain, the email will be sent to your inbox or spam.
PTR records are stored under the IP address in a reversed format. For example, if your IP address is 192.0.2.255, it would be reversed as 255.2.0.192. The reverse DNS lookup - ".in-addr.arpa" is also appended to the reversed IP.
Your final PTR record for 192.0.2.255 would be stored as "255.2.0.192.in-addr.arpa", along with a TTL and a domain associated with this IP address.
To check for PTR records:
No, it is not necessary to have a PTR record. However, it is recommended that you include PTR records to ensure that third-party software, such as email clients, don't send your messages to spam or reject them entirely.
If your DNS host uses a Dynamic DNS, your PTR records will get created automatically. If not, you will have to make your PTS records manually.
The PTR record will be managed by the company that assigned you your IP address.
The main difference between an A and PTR record is that an A record will associate an IP address to a given domain name while a PTR record associates a domain name to a given IP address.
Therefore, an A record helps perform forward DNS lookup (looking up the IP address associated with the domain). In contrast, the PTR record helps in reverse DNS lookups (looking up the domain name associated with the IP address).
In services like Route53, you would put the PTR record in your DNS Zone. You can create a record of type "PTR" and associate a domain to the required IP address.
Try waiting for 24 to 48 hours. DNS records usually take around a day or two to propagate and create. If no record is created after 48 hours, you may have to contact your DNS/IP provider, as the process of manually creating a PTR record may differ across vendors.
Yes, PTR records are widely used to help prevent email clients from rejecting your emails and for other security and verification purposes.
There is no set period for PTR record propagation. It depends on the TTL set to the DNS Record.
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