The
db.192.168.0 Zone Data File
Introduction
The
db.192.168.0 zone data file is the second file we
are creating for our DNS server. As outlined in the
DNS-BIND introduction, this file's purpose is to
provide the IP Address -to- name mappings. Note that
this file is to be placed on the Master DNS server
for our domain.
Constructing db.192.168.0
While we
start to construct the file, you will notice many
similarities with our previous file. Since most
resource records have already been covered and
explained in detail, I will not repeat their
analysis again on this page.
The first
line is our $TTL control statement:
$TTL 3h
Next up is
the Start Of Authority resource record:
0.168.192.in-addr.arpa. IN SOA
voyager.space.net. admin.space.net. (
1 ; Serial
3h ; Refresh after 3 hours
1h ; Retry after 1 hour
1w ; Expire after one week
1h ) ; Negative Caching TTL of 1
hour
As you
can see, everything above, except the first column
of the first line, is identical to the db.space.net
file. The "0.168.192.in-addr.arpa"
entry is my network in reverse order. You simply
take your network address, reverse it, and add an
".in-addr.arpa." at the end.
Name
server resource records are next. The syntax is
nearly the same as the previous file, remember that
we don't enter the full reversed IP Address for the
name servers but only the first 3 octecs which
represent the network they belong to:
; Name Servers defined here
0.168.192.in-addr.arpa. IN NS voyager.space.net.
0.168.192.in-addr.arpa. IN NS gateway.space.net.
If you
find it hard to remember this method, simply remind
yourself that we replace the domain name (previous
file) with the network address reversed, followed by
the ".in-addr.arpa.".
The PTR
resource record follows since we use this to create
our IP Address-to-name mappings:
; IP Address to Name mappings
1.0.168.192.in-addr.arpa. IN PTR admin.space.net.
5.0.168.192.in-addr.arpa. IN PTR
enterprise.space.net.
10.0.168.192.in-addr.arpa. IN PTR gateway.space.net.
15.0.168.192.in-addr.arpa. IN PTR voyager.space.net.
And
now we'll look at the whole file with all its
entries:
$TTL 3h
0.168.192.in-addr.arpa. IN SOA
voyager.space.net. admin.space.net. (
1 ; Serial
3h ; Refresh after 3 hours
1h ; Retry after 1 hour
1w ; Expire after one week
1h ) ; Negative Caching TTL of 1
hour
; Name Servers defined here
0.168.192.in-addr.arpa. IN NS voyager.space.net.
0.168.192.in-addr.arpa. IN NS gateway.space.net.
;
IP Address to Name mappings
1.0.168.192.in-addr.arpa. IN PTR admin.space.net.
5.0.168.192.in-addr.arpa. IN PTR
enterprise.space.net.
10.0.168.192.in-addr.arpa. IN PTR gateway.space.net.
15.0.168.192.in-addr.arpa. IN PTR voyager.space.net.
This
completes the db.192.168.0
Zone data file. Remember the whole purpose of this
file is to provide an IP Address-to-name mapping,
which is why we do not use the domain name in front
of each sentence but the reversed IP Address
followed by the in-addr.arpa. entry.
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