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Community Member

ip address & subnet formula calculation

dear sir,

mind to share how you calculate out which ip address can be use if i got the subnet of 255.255.255.192 and ip address of 172.22.17.X ? I wish to use the ip address of 172.22.17.122 ?

please share.

thanks.

5 REPLIES
Community Member

Re: ip address & subnet formula calculation

Hi,

Check this document

http://www.ietf.org/rfc/rfc1878.txt

//Mikhail Galiulin

Re: ip address & subnet formula calculation

Hi,

With the subnet mask of 255.255.255.192, we can following subnets in 172.22.17.x range.

Subnet 1

*********

Network:172.22.17.0/26

Range: 172.22.17.1-172.22.17.62

Broadcast Address: 172.22.17.63

Subnet 2

*********

Network 172.22.17.64/26

Range: 172.22.17.65 - 172.22.17.126

Broadcast Address: 172.22.17.127

Subnet 3

*********

Network: 172.22.17.128/26

Range: 172.22.17.129 - 172.22.17.190

Broadcast Address: 172.22.17.191

Subnet 4:

*********

Network: 172.22.17.192/26

Range: 172.22.17.193 - 172.22.17.254

Broadcast Address: 172.22.17.255

The ip 172.22.17.122 falls in subnet 2.

HTH

-VJ

Silver

Re: ip address & subnet formula calculation

Hello Chialun,

It all comes down to binary math

With the given mask 255.255.255.192, the fourth octect is interesting.

192 equals 1100.0000 in binary.

Decimal to binary conversion

64 ..... 0100.0000 ==> network

[...]

122 .... 0111.1100

[...]

127 ..... 0111.1111 ==> broadcast

-----------------

192 ... 1100.0000 ==> mask

The range 65 through 126 are valid IP addresses.

HTH

--Leon

* Please rate posts.

Community Member

Re: ip address & subnet formula calculation

There are some FREE ip subnet calculater found on the internet.

http://support.solarwinds.net/updates/MoreSoftware.cfm?Program=92

Community Member

Re: ip address & subnet formula calculation

U could achieve it easily, on this rule:

255.255.255.255

- 255.255.255.192

= 0. 0. 0.063 - Range

Each Subnet has a range of 0-63 addresses.

Counting, the reserved, 1st one to Subnet Address, and last one to BroadCast, easily found, what someone already wrote in the thread.

Best Regards,

Bruno Petr?nio

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