The difference between forward (A) and reverse (PTR) records
Posted by admin on 11 September 2009 09:38 PM
Forward records, or A records, are those which translate from machine names to ip addresses. These are the most commonly used records. A typical A record is constructed as follows:|
gigenet.test.com. IN A 192.168.1.1
(this example shows an A record which correlates the machine name gigenet.test.com to the IP address 192.168.1.1)
Reverse records, or PTR records, are those which translate from ip address to machine names. They are typically used for security tests. The IP address of a machine is reversed, and then the suffix in-addr.arpa is appended. A typical PTR record is:
220.127.116.11.in-addr.arpa. IN PTR gigenet.test.com.
(this example shows a PTR record which correlates the IP address 192.168.1.1 to the machine name gigenet.test.com)