What is Reverse DNS?

Reverse DNS (Domain Name Program) lookup, also identified by the acronym (rDNS), is the method by which an individual can appear up a host name given a certain IP address. Reverse DNS is also recognized in some places as reverse resolving. It is the opposite of DNS lookup, by which an individual looks up an IP address given a specific host name.

Why use Reverse DNS?

A reverse DNS lookup is generally performed for troubleshooting purposes. Frequently, tools like a traceroute or a ping will do a reverse DNS lookup to decide the flow of site visitors from a single point to another. An additional widespread location for reverse DNS lookup is when accessing a persons e-mail. Numerous modern day e mail providers will do reverse DNS lookups de colores online to determine if an e-mail was sent from a known spam address. Finally, reverse DNS can be utilized to make certain that there is a appropriate relationship in between the owner of a server and the owner of a domain name. This strategy, recognized as Forward Confirmed reverse DNS (FCrDNS) is employed to put a cease to phishing sites and spammers.

What is IPv4 Reverse DNS lookup?

IPv4 Reverse DNS is a first communion dresses kind of reverse DNS that makes use of a reverse IN-ADDR entry with the particular domain in-addr.arpa. The IP address represented in the in-addr.arpa domain is written in reverse order to the usual way that the IP address is written. For instance, if a individual was performing a reverse domain lookup for an address such as 192.168.1.1, he would do the lookup utilizing 1.1.168.192.in-addr.arpa.

What is IPv6 Reverse DNS lookup?

IPv6 Reverse DNS lookup is a sort of reverse DNS that catholic church supplies uses the special domain ip6.arpa. Unlike IPv4 Reverse DNS lookup, IPv6 Reverse DNS lookup does not use the common IP address style of hunting up host names. Instead, it utilizes a sequence of nibbles, or 4 bit aggregations, in reverse order with each quantity separated by a period. For example, if a individual was performing a reverse domain lookup for an address such as 2001:0db8:::::1428:57ab he would do the lookup employing b.a.7.five.8.two.4.1.....8.b.d..1...2.ip6.arpa.

What happens when there are many host names assigned to 1 IP address?

A reverse DNS lookup will be able to decide all of the host names associated with a particular IP address, though this practice is at times frowned upon. A lot of low-cost net hosting plans will offer shared virtual hosts where many websites share space on the very same IP address. Although this does not impact the validity of the info returned by a reverse DNS lookup, it can lead to problems with other services.