Static IP is allocated to an ISP client under assurance that such IP will never be changed. This warranty is given under a contract between the parties. In contrast, dynamic IP is allocated to the client without any guarantee that it will not be changed by the ISP.
Some people believe that the dynamic IP is one that is constantly changed by the ISP. But this...
Generic rDNS refers to a sequential name pattern for a large set of IPs in a datacenter or ISP. The generic rDNS is immediately set when the ISP receives the IP block, much before the IP is allocated on a real machine. Therefore, generic rDNS is a name given to IP and not a name given to host.
Examples of generic rDNS
Generic rDNS usually follows a...
Forward-confirmed reverse DNS (FCrDNS) is an rDNS configuration that defines strong relationship between IP and domain. FCrDNS implementation depends on a joint action between the IP administrator and the domain administrator. When FCrDNS is valid, there is a guarantee that the domain owner has responsibility for the use of IP.
How to check FCrDNS for IPv4
To check the FCrDNS, you must query the rDNS. As an...
Reverse DNS (rDNS) is the naming method of the machine that is using a given IP and is defined by the IP block administrators through the PTR record in DNS.
How to discover the rDNS of an IPv4
To discover the rDNS of an IPv4, just consult the PTR of the IP reverse form with ".in-addr.arpa". As an example, the IP "209.85.218.43" is transformed into "43.218.85.209.in-addr.arpa" and...
Uma das principais políticas atualmente utilizadas pelos servidores de e-mail no combate ao SPAM, é a checagem do DNS reverso.
Utilizando-se somente da checagem do DNS reverso, podem ser eliminados até 70% dos casos de SPAM....
