How do I setup reverse dns for my IP?

What is the reverse DNS?

Reverse DNS is an IP address to domain name mapping – the opposite of Forward DNS which maps domain names to IP addresses.

Comparison :

## FORWARD LOOKUP ##
host example.com
example.com has address 195.86.50.27

## REVERSE LOOKUP ##
host 195.86.50.27
195.86.50.27.in-addr.arpa domain name pointer www.example.com.

What does the Reverse DNS serve for?

The Reverse DNS is one of the basic requirements for running some Internet protocols. It is also often used as a spam filter to determine whether the IP address of the incoming message matches an authenticated domain name and to block the message if it doesn’t.

Who controls the reverse DNS?

Reverse DNS is controlled by the owner of the IP address (probably your SIP).

Configuring the reverse DNS

Lets setup PTR record for the IP address ‘195.86.50.27’. It should be pointed to ‘your.site.name’.

Add the new zone to the ‘named.conf’ file as follows :

add zone 195.86.50.27.in-addr.arpa under your zone “example.com”

nano /etc/named.conf

zone "example.com" {
type master;
file "/var/named/example.com.hosts";
};
zone "195.86.50.27.in-addr.arpa" {
type master;
file "/var/named/27.50.86.195.rev";
};

then edit it
nano /var/named/27.50.86.195.rev

$ttl 38400
195.86.50.27.in-addr.arpa. IN SOA ns1.example.com. webmaster.example.com. (
1361687161
10800
3600
604800
38400 )
195.86.50.27.in-addr.arpa. IN NS ns1.example.com.
195.86.50.27.in-addr.arpa. PTR example.com.

save and restart your dns
service named start