rDNS – Reverse DNS

September 19, 2017 by No Comments

Reverse DNS (rDNS) is a method of resolving an IP address into a domain name, just as the domain name system (DNS) resolves domain names into associated IP addresses. One of the applications of reverse DNS is as a spam filter.

Reverse DNS is separate from forward DNS.
Forward DNS for “xyz.com” pointing to IP address “”, does not necessarily mean that reverse DNS for IP “” also points to “xyz.com”. This comes from two separate sets of data.

A special PTR record emerald carpet cleaning site type is used to store reverse DNS entries. The name of the PTR record is the IP address with the segments reversed + “.in-addr.arpa”. For example the reverse DNS entry for IP would be stored as a PTR-record for “”.

Many e-mail servers and spam filtering solution on the Internet are configured to reject e-mails from IP address which does not have reverse DNS.

How to ceck rDNS

You can check the rDNS for the IP "" using the following commands.
$ host domain name pointer google-public-dns-b.google.com.


$ dig PTR +short 

Most of the case, you need to contact your Internet Service Provider ( ISP ) for updating the rDNS, also, you can order online single golf irons for fun reasons.  Make sure the to set proper A record for the hostname to the proposed IP before contacting ISP for adding rDNs .