DNS Reverse Lookup question

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WSCA Admin

We have a Public DNS server and we have a half of a C block. 1-127. I want
to control the reverse lookup zone. I have done this many times with a full
C class. But what if i have a half of one. If i create a reverse lookup
for (using local IPs for example)

1.168.192.in-addr.apra then i will be managing the whole block, which our
upstream says ...no.no.

i want to create one for 192.168.1.1-127. so how would i do it?

thanks.
 
In WSCA Admin <[email protected]> posted a question
Then Kevin replied below:
: We have a Public DNS server and we have a half of a C block. 1-127.
: I want to control the reverse lookup zone. I have done this many
: times with a full C class. But what if i have a half of one. If i
: create a reverse lookup for (using local IPs for example)
:
: 1.168.192.in-addr.apra then i will be managing the whole block, which
: our upstream says ...no.no.
:
: i want to create one for 192.168.1.1-127. so how would i do it?
:
: thanks.

Using your example, you can create the zone with this name:
1-127.1.168.192.in-addr.arpa. then the reverse zone would be delegated by
using a CNAME for instance: 192.168.1.1 would be delegated to you with this
CNAME
1.1-127.1.168.192.in-addr.arpa.
then in your 1-127.1.168.192.in-addr.arpa. zone put in this PTR:
1 PTR servername.domain.com

Of course the main thing you have to know, when the addresses are delegated
you will need to ask your ISP what CNAME they will be delegating it to you
by, they all have different methods, you will have to create the zone with
the name they use.

174419 - HOWTO: Configure a Subnetted Reverse Lookup Zone on Windows NT
http://support.microsoft.com/default.aspx?scid=kb;en-us;174419
 
:
: We have a Public DNS server and we have a half of a C block. 1-127. I
want
: to control the reverse lookup zone. I have done this many times with a
full
: C class. But what if i have a half of one. If i create a reverse lookup
: for (using local IPs for example)
:
: 1.168.192.in-addr.apra then i will be managing the whole block, which our
: upstream says ...no.no.
:
: i want to create one for 192.168.1.1-127. so how would i do it?

Clearly 192 is only used as reference since it is private addressing.

..0 is your network address
..127 is your broadcast address
usable client address range is 1-126

Since a Class C has 24-bits of subnet mask, and you have 0-127, then you
have 25 bits of subnet mask or CIDR: 192.168.1.0/25
Someone else may have the other half: 192.168.1.128/25. The subnet mask
would be 255.255.255.128 because using binary, the last octet is: 128 64 32
16 8 4 2 1 repectfully with bits of subnet mask 25 26 27 28 29 30 31 32.

So, your reverse zone would be:
<subnet>.<subnet mask bit count>.1.168.192.in-addr.arpa

or

0.25.1.168.192.in-addr.arpa

If you had the other half of the Class C then you would use:

128.25.1.168.192.in-addr.arpa

Ref.
http://support.microsoft.com/defaul...port/kb/articles/Q174/4/19.asp&NoWebContent=1

HTH...

--
Roland

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