As the title says, I want to know properly what is PTR record and how it is created. I know it is used when reverse DNS is done. But what is the use of PTR record?
Please guide this newbie here :P
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As the title says, I want to know properly what is PTR record and how it is created. I know it is used when reverse DNS is done. But what is the use of PTR record?
Please guide this newbie here :P
A PTR record is what lets someone do a "reverse" DNS lookup - that is, they have your IP address and want to know what your host/domain is. A PTR record lists an IP address and points it to a Fully Qualified Domain.
A PTR record, also referred to as a Reverse IP record, is an "A" record in reverse. In the case of an "A" record, DNS lists a Fully Qualified Domain such as www.techarena.in and points it to an IP address. A PTR record lists an IP address and points it to a Fully Qualified Domain such as www.techarena.in. So basically PTR records resolve IP addresses into hostnames.
For example, the A record for forums.techarena.in resolves this domain name to 102.44.102.44: (just an example)
forums.techarena.in | A | IN | 100000 | 102.44.102.44
And then the PTR record resolves 102.44.102.44 back to forums.techarena.in:
102.44.102.44.in-addr.arpa. | PTR | IN | 100000 | forums.techarena.in
As you can see, you need to type the reversed IP address and add "in-addr.arpa." to it to query for PTR records. This is called reverse DNS.
Not every IP address has a corresponding PTR record. In fact, if you took a random sampling of addresses your firewall blocked because they were up to no good, you'd probably find most have no PTR record. That's also apt to be true for mail spammers, or their PTR doesn't match up on their IP you get a result, but if you look up that result you might not get the same IP you started with. That's why PTR records have become important.
A PTR record associates an IP address with a canonical name. PTR records should point to a name that can be resolved back to the IP address. The name of the pointer record is not the IP address itself, but is the IP address’ four IP octets in reverse order followed by IN-ADDR.ARPA.
A PTR record is what lets someone do a "reverse" DNS lookup - that is, they have your IP address and want to know what your host/domain is.
PTR record is commonly needed only for mail servers. You can find PTR record for your IP at Find PTR record and check it in blacklist at Blacklist checker