What is Reverse DNS?

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Reverse DNS (Domain Name Technique) lookup, also recognized by the acronym (rDNS), is the procedure by which an individual can appear up a host name given a distinct IP address. Reverse DNS is also identified in some areas as reverse resolving. It is the opposite of DNS lookup, by which an individual looks up an IP address given a particular host name.

Why use Reverse DNS?

A reverse DNS lookup is generally performed for troubleshooting purposes. tour baptismal bowl Frequently, tools like a traceroute or a ping will do a reverse DNS lookup to figure out the flow of site visitors from one point to an additional. One more common place for reverse DNS lookup is when accessing a persons e-mail. Several modern e mail providers will do reverse DNS lookups to determine if an email was sent from a recognized spam address. Lastly, reverse DNS can be utilized to make certain that there is a correct relationship between the owner of a server and the owner of a domain name. This method, identified as Forward Confirmed reverse DNS (FCrDNS) is utilized to put a vestments stop to phishing web sites and spammers.

What is IPv4 Reverse DNS lookup?

IPv4 Reverse DNS is a kind of reverse DNS that makes use of a reverse IN-ADDR entry with the unique 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 example, if a individual was performing a reverse domain lookup for an address such as 192.168.1.1, he would do the lookup employing 1.1.168.192.in-addr.arpa.

What is IPv6 Reverse DNS lookup?

IPv6 Reverse DNS lookup is a kind a guide to censer of reverse DNS that makes use of the special domain ip6.arpa. Unlike IPv4 Reverse DNS lookup, IPv6 Reverse DNS lookup does not use the standard IP address style of looking up host names. Rather, it utilizes a sequence of nibbles, or four bit aggregations, in reverse order with each and every quantity separated by a period. For instance, if a person was performing a reverse domain lookup for an address such as 2001:0db8:::::1428:57ab he would do the lookup making use of b.a.7.five.8.two.four.1.....8.b.d..1...two.ip6.arpa.

What happens when there are multiple host names assigned to a single IP address?

A reverse DNS lookup will be in a position to establish all of the host names linked with a specific IP address, though this practice is at times frowned upon. Several inexpensive internet hosting plans will provide shared virtual hosts exactly where many web sites share space on the identical IP address. Although this does not influence the validity of the info returned by a reverse DNS lookup, it can lead to issues with other services.