Solved

Help understanding subnet addressing

Posted on 2007-12-05
9
226 Views
Last Modified: 2010-04-21
Hello -

Sorry is this is a simple request - but I am not a networking person...

I am provided a Subnet address of 10.xx.xx.0/24

Does this mean I can have a host range of 10.xx.xx.0 - 10.xx.xx.254

Thanks
0
Comment
Question by:newtontech4
9 Comments
 
LVL 1

Accepted Solution

by:
tonux earned 125 total points
Comment Utility
Hi,
in this subnet, there must be at least one address for the Router (I.e. default Gateway for hosts)
So you have 2^8 adresses, minus 1 for the router. so it's 255 addresses.
By convention the ".0" address is not use for hosts. and the ".255" is used for broadcasting on this subnet.
So if you have a default GW address on ".254" (which is a common convention to) then you have .1 -> .253 addresses available for hosts.

hope this helps
Tonux
0
 
LVL 8

Assisted Solution

by:Jeff Perry
Jeff Perry earned 125 total points
Comment Utility
Yes and No

the /24 means your subnet mask is 255.255.255.0 so your Network is 10.xxx.xxx.0 Your first valid host is 10.xxx.xxx.1 and your last valid host is 10.xxx.xxx.10.xxx.xxx.254 with a broadcast address of 10.xxx.xxx.255
0
 
LVL 77

Assisted Solution

by:Rob Williams
Rob Williams earned 125 total points
Comment Utility
Some times a "picture" is worth 1000 words, a very useful on-line tool that will outline all of the above in a very clear list is:
http://tstools.co.uk/ipcalc.php

Should you want a better understanding the following site is great:
http://www.learntosubnet.com
0
 
LVL 51

Assisted Solution

by:Keith Alabaster
Keith Alabaster earned 125 total points
Comment Utility
Hey Rob - Merry Chrsitmas (or nearly)

Newton, no - it does not mean that <<Does this mean I can have a host range of 10.xx.xx.0 - 10.xx.xx.254>>

Standard IPv4 ip addresses are 32 bits long and split into 4 'octets', each being 8 bits long. IP addresses are broken down into a network portion and a host portion. The subnet mask or bit mask tells you how many of the 32 bits are part of the network and how many can be used as hosts.

In your example of /24, this tells us that the first 24 bits of the ip address given are for the network and the rest are hosts.
so 10.0.0 is the network (3 x 8-bit octets) and the last octet is the host portion (0 - 255 = 256 addresses). You always take 2 off this number as Rob mentions for the Network ID and the broadcast leaving 254 useable start ing at .1 in this example.

Keith
0
What Should I Do With This Threat Intelligence?

Are you wondering if you actually need threat intelligence? The answer is yes. We explain the basics for creating useful threat intelligence.

 
LVL 77

Expert Comment

by:Rob Williams
Comment Utility
Hi Keith ! Same to you. It's approaching quickly.
For the record that was not my post <G>.  ==>""You always take 2 off this number as Rob mentions "
0
 
LVL 51

Expert Comment

by:Keith Alabaster
Comment Utility
lol - I'm getting old. I'm sure you would have pointed it out though as it is correct :)
0
 
LVL 77

Expert Comment

by:Rob Williams
Comment Utility
I was thinking it. Does that count :-)
0
 

Author Closing Comment

by:newtontech4
Comment Utility
thanks for your help -
0
 
LVL 77

Expert Comment

by:Rob Williams
Comment Utility
Thanks newtontech4.
Cheers !
--Rob
0

Featured Post

What Security Threats Are You Missing?

Enhance your security with threat intelligence from the web. Get trending threat insights on hackers, exploits, and suspicious IP addresses delivered to your inbox with our free Cyber Daily.

Join & Write a Comment

We recently endured a series of broadcast storms that caused our ISP to shut us down for brief periods of time. After going through a multitude of tests, we determined that the issue was related to Intel NIC drivers on some new HP desktop computers …
Don’t let your business fall victim to the coming apocalypse – use our Survival Guide for the Fax Apocalypse to identify the risks and signs of zombie fax activities at your business.
Viewers will learn how to connect to a wireless network using the network security key. They will also learn how to access the IP address and DNS server for connections that must be done manually. After setting up a router, find the network security…
In this tutorial you'll learn about bandwidth monitoring with flows and packet sniffing with our network monitoring solution PRTG Network Monitor (https://www.paessler.com/prtg). If you're interested in additional methods for monitoring bandwidt…

744 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

15 Experts available now in Live!

Get 1:1 Help Now