# Thread: IP Question, this makes no sense 2me!

1. Web Hosting Master
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Dec 2001
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## IP Question, this makes no sense 2me!

Okay,

a /30 = 4IP's

a /27 = 32IP's

This makes no sense to me, could someone with more network experience explain this to me?

Join Date
Jun 2002
Posts
117

## Re: IP Question, this makes no sense 2me!

/30 = 4 IP's
/29 = 8 IP's
/28 = 16 IP's
/27 = 32 IP's
/26 = 64 IP's
/25 = 128 IP's
/24 = 256 IP's
/23 = 512 IP's
/22 = 1024 IP's
/21 = 2048 IP's
/20 = 4096 IP's
/19 = 8192 IP's

From the ARIN.net website:

*The minimum block of IP address space assigned by ARIN is a /20. Smaller blocks obtained directly from ARIN are the least likely to be globally routable.

Originally posted by jdp29053
Okay,

a /30 = 4IP's

a /27 = 32IP's

This makes no sense to me, could someone with more network experience explain this to me?

3. Web Hosting Master
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I guess what im trying to figure out is WHY /19 would equal 8192 IP's?

1+1=2
/19=8192, this is what doesnt make sense.. i guess what im trying to say is i dont understand the formula or equation they are using that gives them justification to describe 8192 IP's as a block of /19.

Thats what im trying to figure out.. see what i mean?

4. Web Hosting Master
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When you convert the IP to its bits equivalent, it probably makes more sense.

Here is an article which aims to explain this addressing issue :-

Hope that helps.

Edwin

5. Web Hosting Master
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Look at the pattern, it starts at /30 as a designator for 4 then /29 for 8, it doubles each time. /19 is the designator for 8192 or double /20 4096.
It is just their code or designator number.

6. Junior Guru Wannabe
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Mar 2001
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Originally posted by jdp29053
I guess what im trying to figure out is WHY /19 would equal 8192 IP's?
An IP number consists of 32 bits. "/19" means that 19 bits out of those 32 are used to designate the network (alternatively you can say that 19 bits are used for the netmask). That leaves 32-19 = 13 bits to describe hosts on that particular network. 13 bits is enough to describe 2^13 = 8192 different hosts.

Hope that helps.

7. Web Hosting Master
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So there is no particular reason why they use /30 for a 4IP block then..

Its just a way of naming the block amount?
I thought there might be some kind of formula or equation to explain the /" " for representing "x" amount of IP's.

8. Web Hosting Master
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## Oh okay

Thanks spock..
Sorry i made the post above while you where writting that reply i guess..

That makes sense.
Thank you

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