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DNS Subnet Sanity Check

I need to create CIDR's for a newly created Web Application Firewall.

If I wanted to write subnetting for the following two IP Addresses:

220.100.106.8
220.100.106.9

Would it be written like:

220.100.106.8/31

(e.g. /31)?

Thanks for the "Friday" Sanity Check. :-)
0
Tessando
Asked:
Tessando
1 Solution
 
MichelangeloConsultantCommented:
Correct.

If in doubt, use a subnet calculator such as
http://www.subnet-calculator.com/cidr.php
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TessandoIT AdministratorAuthor Commented:
Thank you.
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nociSoftware EngineerCommented:
WRT. Subnetting

Except that with subnetting, /31 is a bit of an oxymoron.
In a subnet the base address (lowest) = network address (meaning THIS system on this net work, to all of the nodes)
and the Highest address is ALL the systems on the subnet....  (the ultimates:    0.0.0.0  (aka ME), 255.255.255.255 (aka Everyone on this network)...
but on 192.168.1.0/24  then 192.168.1.0 = network address, 192.168.1.255 is broadcast.

In your network:
220.100.106.8 = Network
220.100.106.9 = Broadcast...
Leaving no addresses for nodes.......

The Smallest Subnet would be /30 leaving 20 addresses. Often seen in connections between ISP & Customers. or links that carry tunnels.

The expression CAN be used in ACCESS masks (like for Firewall filters). meaning you want to manage .8 & .9 different from others.
Not exactly a Subnet...
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