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How to define a rule in Windows server 2008 firewall to be applied to an IP range. For example blocking IPs which start with 202 I mean all IPs which meet 202...*

There are two options when creating a new rule:

  1. This IP address or subset:

  2. This IP address range:

How should I define such a wide range ?

Xaqron
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  • I'd first ask the question, "why are you blocking all those IPs in the first place?" A blanket answer wouldn't fit here, nor would it be beneficial to you in the long term. – surfasb Aug 02 '11 at 17:24
  • That is the range between 202.0.0.0 to 202.255.255.255. I assume that you mean IPv4. – soandos Aug 02 '11 at 17:23
  • Yes I mean IP v4. I was wondering if this wide range has a negative performance issue or not. – Xaqron Aug 02 '11 at 17:25

1 Answers1

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The range begins at 202.0.0.0 and ends at 202.255.255.255. You can also represent it as 202.0.0.0/8.

Why /8?

An IPv4 address is a 32-digit binary number that has been conveniently divided into 4 groups. The address 202.0.0.0 expressed in binary is

11001010 00000000 00000000 00000000

In this context /8 means "match the first 8 binary digits", or any address that begins with 202..

Read all about it at the Wikipedia article for Classless Inter-Domain Routing.

William Jackson
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