Cisco Support Community
cancel
Showing results for 
Search instead for 
Did you mean: 
Announcements

Welcome to Cisco Support Community. We would love to have your feedback.

For an introduction to the new site, click here. If you'd prefer to explore, try our test area to get started. And see here for current known issues.

New Member

Urgent Subnetting help needed

Hi All,

Could anyone be kind to help with the first six subnets of the following address 172.23.0.0/27 WITHOUT inclusion of subnet zero and please explain to help my understanding.

Regards

Newnetman

6 REPLIES
Hall of Fame Super Bronze

Re: Urgent Subnetting help needed

27 bits are on

11111111.11111111.11111111.11100000

5 bits are variable

2^5 = 32

You need a subnet ID and a broadcast address on each subnet, so starting with the first subnet.

172.23.0.0 [subnet ID]

172.23.0.1-30 [IP for Host]

172.23.0.31 [broadcast for that subnet]

172.23.0.32 [subnet ID]

172.23.0.33-62 [IP for Host]

172.23.0.63 [broadcast for that subnet]

172.23.0.64 [subnet ID]

172.23.0.65-94 [IP for Host]

172.23.0.95 [broadcast for that subnet]

And I will let you do the last 3. The logic is adding 32 to the subnet ID and broadcast address, whatever you have in between those 2 values, they are your IPs for the hosts.

HTH,

Hall of Fame Super Blue

Re: Urgent Subnetting help needed

Your explantion is better :)

Hall of Fame Super Bronze

Re: Urgent Subnetting help needed

Both equal in value to the community :)

Hall of Fame Super Blue

Re: Urgent Subnetting help needed

Hi

172.23.0.32

172.23.0.64

172.23.0.96

172.23.0.128

172.23.0.160

172.23.0.192

You can use binary to write this out but a quick way to work it out

/27 = 255.255.255.224

256 - 224 = 32

So you subnets go up in increments of 32.

HTH

Jon

New Member

Re: Urgent Subnetting help needed

Hi,

I think EdisonOrtiz has explained it well, hence rated.

I will just add into that. This document explains it all.

http://www.3com.com/other/pdfs/infra/corpinfo/en_US/501302.pdf

HTH

Shaheen

New Member

Re: Urgent Subnetting help needed

Hi All,

I am most delighted for all your magnificent responses.

I am so proud to call you all my invisible mentors.

May you all be bountifully blessed.

regards

144
Views
8
Helpful
6
Replies