Solved

IP addressing

Posted on 2010-09-15
8
1,071 Views
Last Modified: 2013-01-20
I have very little knowledge of IP addressing and I would appreciate some help here

I have an assigned range of 75.137.45.144/28. How many machines can I connect to it and can I make it into two equal sized subnets? How?  Is there a Math formula to figure this stuff out??
0
Comment
Question by:dawber39
  • 3
  • 2
  • 2
  • +1
8 Comments
 
LVL 35

Expert Comment

by:mccarl
Comment Utility
You can have up to 14 devices in this range. For your info the subnet mask would be 255.255.255.240

If you want two subnets, then they could have only 6 devices each. They would have ranges of 75.137.45.144/29 and 75.137.45.152/29 and the subnet mask for these two subnets would be 255.255.255.248
0
 
LVL 68

Accepted Solution

by:
Qlemo earned 500 total points
Comment Utility
with a /28 you have 32-28 = 4 bits = 16 addresses left for your hosts. You need to subtract two for the reserved addresses of all-zero and all-one bits, so in fact you can use 14 addresses. If you subnet that, you loose 2 addresses per subnet for the same reason. Your subnets would then be
75.137.45.144/29 with .145 - .150
75.137.45..152/29 with .153 - .158
that are 6 addresses per subnet = 12 overall.

The /28 part tells us how much bits from the left to the right are assigned to the network. Each part of the address is a single byte = 8 bit, 4 parts = 32 bits, and /28 is 32-4, which means 4 bits are left for the hosts.
We can only add bits on the highest part of the host addresses for implementing subnets, so the next bit to use for a subnet is bit 29, which has a value of 8 (2 power 3).That is why the next subnet starts at 152 (144+8).
0
 
LVL 24

Expert Comment

by:rfc1180
Comment Utility
>I have an assigned range of 75.137.45.144/28. How many machines can I connect to it and can I make it into two equal sized subnets?

This depends on whether or not you are assigning this range to an interface; if all you are doing is defining static one to one NAT, then you can use all 16 addresses; if you are however, assigning this to a physical interface on a firewall/router, you will then need 1 IP address for the physical interface then you will have 13 usable addresses for your hosts on this LAN.

Billy
0
 

Author Comment

by:dawber39
Comment Utility
I appreciate the efforts of all of you - but Qlemo gave me a better explanation of how - thank you all
0
IT, Stop Being Called Into Every Meeting

Highfive is so simple that setting up every meeting room takes just minutes and every employee will be able to start or join a call from any room with ease. Never be called into a meeting just to get it started again. This is how video conferencing should work!

 

Author Closing Comment

by:dawber39
Comment Utility
Excellent
0
 
LVL 35

Expert Comment

by:mccarl
Comment Utility
If you "appreciate the efforts of all" you should really be sharing the points... but whatever!
0
 
LVL 24

Expert Comment

by:rfc1180
Comment Utility
too bad you can't block authors!
0
 

Author Comment

by:dawber39
Comment Utility
Wow - all I did was ask how - and Qlemo was quite definitive in his explanation - I am sorry if I hurt your feelings
0

Featured Post

Maximize Your Threat Intelligence Reporting

Reporting is one of the most important and least talked about aspects of a world-class threat intelligence program. Here’s how to do it right.

Join & Write a Comment

Article by: rfc1180
The Maximum Segment size (MSS) is an important consideration when troubleshooting connectivity via the Internet/Intranet. As the packets are routed via the Internet/Intranet, the packets must traverse through multiple routers in the path between two…
Creating an OSPF network that automatically (dynamically) reroutes network traffic over other connections to prevent network downtime.
Excel styles will make formatting consistent and let you apply and change formatting faster. In this tutorial, you'll learn how to use Excel's built-in styles, how to modify styles, and how to create your own. You'll also learn how to use your custo…
Get a first impression of how PRTG looks and learn how it works.   This video is a short introduction to PRTG, as an initial overview or as a quick start for new PRTG users.

771 members asked questions and received personalized solutions in the past 7 days.

Join the community of 500,000 technology professionals and ask your questions.

Join & Ask a Question

Need Help in Real-Time?

Connect with top rated Experts

11 Experts available now in Live!

Get 1:1 Help Now