How to add reverse DNS delegation for RIPE

Let’s say we want to add reverse DNS delegation for the IP block 123.234.12.0/24

The first step of the configuration is on the nameserver, BIND on our case.

Create the relevant reverse DNS file on /var/named/rev and then edit the file:

cd /var/named/rev
touch 123.234.12
vim 123.234.12

The file contents should be like the following:

$TTL 3D
@       IN      SOA     ns1.rackdc.com. postmaster.rackdc.com. (
                        2018112201   ; Serial, todays date + todays serial
                        8H      ; Refresh
                        2H      ; Retry
                        4W      ; Expire
                        1D)     ; Minimum TTL
                                ; Created on http://root0.net 2005-10-27
                 NS             ns1.rackdc.com.
                 NS		ns2.rackdc.com.
                 
$ORIGIN 12.234.123.in-addr.arpa.


12		PTR		rackdc.com.

After configuring this file with correct details, edit the file /etc/named.conf to include the file you’ve just created.

vim /etc/named.conf

Add the following line in the file:

zone "12.234.123.in-addr.arpa" { notify yes; type master; file "/var/named/rev/123.234.12";allow-query { any; };};

Finally, restart the DNS service.

service named restart

It is important to complete this step before creating an object in RIPE.