Reverse DNS - IP Address to Name (db.yourIPreversed)

From Debian Clusters

This is the fourth page of a five part tutorial on setting up Name Service: DNS and BIND. The full tutorial includes

db.yourIPreversed

/etc/bind/db.yourIPreversed is the file responsible for reverse DNS, finding a host's domain name from its IP address. This is the db.yourIPreversed file we referred to in the /etc/bind/named.conf.local file two sections ago. It needs to be manually created.

The first parts, the TTL, SOA record, and the nameserver should be set up as in Forward DNS - Name to IP Address (db.yourdomain). Look back to that page for a refresher. You should be able to copy it, and then change the places that specify the domain. In mine, references to raptor.loc. needed to be changed to 1.168.192.in-addr.arpa.

$TTL    24h

1.168.192.in-addr.arpa.   IN  SOA   eyrie.raptor.loc.   root.raptor.loc (
        2007062800 ; serial number
        3h         ; refresh time
        30m        ; retry time
        7d         ; expire time
        3h         ; negative caching ttl
)

# Nameservers
1.168.192.in-addr.arpa.  IN  NS  192.168.1.254

PTR Records

Instead of address records, however, the information for getting hostnames from IP addresses needs to be specified. When DNS looks up a host name by IP address, it reverses the order of the octets and appends in-addr.arp as the IP "hostname". This record needs to store those records and point to what their real domain names are. These are called the PTR records. The format for these is

<IP with order reversed>.in-addr.arpa. IN PTR <full domain name>.

My full /etc/bind/db.1.168.192 file is below.

$TTL    24h

1.168.192.in-addr.arpa.   IN  SOA   eyrie.raptor.loc.   root.raptor.loc (
        2007062800 ; serial number
        3h         ; refresh time
        30m        ; retry time
        7d         ; expire time
        3h         ; negative caching ttl
)

; Nameservers
1.168.192.in-addr.arpa.  IN  NS  192.168.1.254.

; Hosts
254.1.168.192.in-addr.arpa.     IN PTR  eyrie.raptor.loc.
200.1.168.192.in-addr.arpa.     IN PTR  gyrfalcon.raptor.loc.
201.1.168.192.in-addr.arpa.     IN PTR  kestrel.raptor.loc.
202.1.168.192.in-addr.arpa.     IN PTR  owl.raptor.loc.
203.1.168.192.in-addr.arpa.     IN PTR  goshawk.raptor.loc.
204.1.168.192.in-addr.arpa.     IN PTR  osprey.raptor.loc.
205.1.168.192.in-addr.arpa.     IN PTR  peregrine.raptor.loc.
206.1.168.192.in-addr.arpa.     IN PTR  kite.raptor.loc.
207.1.168.192.in-addr.arpa.     IN PTR  eagle.raptor.loc.
208.1.168.192.in-addr.arpa.     IN PTR  harrier.raptor.loc.