Share your knowledge at the LQ Wiki.
Go Back > Forums > Linux Forums > Linux - Networking
User Name
Linux - Networking This forum is for any issue related to networks or networking.
Routing, network cards, OSI, etc. Anything is fair game.


  Search this Thread
Old 11-03-2003, 06:50 AM   #1
LQ Newbie
Registered: Oct 2003
Location: Delhi
Posts: 3

Rep: Reputation: 0
Problem of Subnetting

hi frds
myself is nit
i have some problem in networking.
my organisation have a LAN addressing system.
but no properly configure many times users gave a static ip to his system as same as
server ip. so its a big problem.
i m sending detail of my LAN addressing system.


plz send immd reply
Old 11-03-2003, 07:22 AM   #2
Senior Member
Registered: Oct 2003
Posts: 3,057

Rep: Reputation: 58
When a user grabs your server IP address, smack them up side the head and tell them not to do that!
Set up a DHCP server with a subnet range and EXCLUDE the server addresses from that range. Then just let the clients get the ip address automatically.
Old 11-04-2003, 02:51 AM   #3
LQ Newbie
Registered: Oct 2003
Location: Delhi
Posts: 3

Original Poster
Rep: Reputation: 0
hi homey
but dear i don't want to use DHCP Server.
i want to distribute subnet like they can not give the ip like
& other .
actually my subnet mask is
my range is
so i want to further rearrange these ip.
plz help me
Old 11-04-2003, 03:46 AM   #4
LQ Guru
Registered: Apr 2002
Location: Atlanta
Distribution: Gentoo
Posts: 1,280

Rep: Reputation: 47
to setup up classless subnetting, you will need a router for each network you want. you will need all of these routers to be able to talk to each other (with a small netowrk RIP is good, OSPF is better for long run). Or you can setup the Routing tables yourself manually. You could buy one big 6509 from CISCO and use it. One big router that acts as several routers, does bridging....costs a LOT.

It would be hard to explain everything you need to do to set this up as it is a TRUE networking problem and would take more than a post on this website to answer your question. you have several options to go with.

as for the problem with people stealing the ip of the will have to use DHCP to help on large networks, ip conflicts are hard to avoid. (it gets even worse when no-so-smart users accidently run their own DHCP servers on accident).

to re-arrange the IPs, you need to know how many subnetworks you need. once you do this, you'll know how many bits you need off your base 172.16/24.

for instance, if you need 8 subnetworks, you would do this:

you have a class B assignment, meaning u can play with 16 bits (the last 16). If you need 8 subnetworks, 8 networks= 3 bits (0 - 7, 7 = 0b111). This means you will need 4 of the last 16 bits to make up a network which means you will have the following:

10101100.00010000.00000000.00000000 = - /
10101100.00010000.00100000.00000000 = -
10101100.00010000.01000000.00000000 = -
10101100.00010000.01100000.00000000 = -
10101100.00010000.10000000.00000000 = -
10101100.00010000.10100000.00000000 = -
10101100.00010000.11000000.00000000 = -
10101100.00010000.11100000.00000000 = -

(you cant use the 1st and last IPs in each list, explained below)

you will have 13 bits to play with on each network giving you

2^13 - 2 total hosts on each network
the -2 is because you cant use .0 or .255 because .0 specifies a network and 255 is broadcast.

if u wanted 10 subnets you'd have to use up 4 bits to specify a network and u'd have to redo that table.

if your network will really use all those IP addresses (or close). you may want to hire a network guy, or hire a consultant for such a large network. (im available for hire )

also, for a network this large, DHCP is almost a must. and your gateways should end in .1, this is not a witten convention but .51 is just a bad number to pick for a gateway address.

Last edited by Robert0380; 11-04-2003 at 03:51 AM.


Thread Tools Search this Thread
Search this Thread:

Advanced Search

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off

Similar Threads
Thread Thread Starter Forum Replies Last Post
subnetting: how it works.. kool124 Linux - General 1 10-02-2005 01:49 PM
Problem related with subnetting myself_rajat Linux - Networking 1 12-07-2004 04:23 AM
subnetting juanb Linux - Networking 1 06-30-2004 10:23 AM
subnetting Fabian030 General 4 09-11-2003 03:11 AM
subnetting juanb Linux - Networking 3 08-26-2003 10:56 AM

All times are GMT -5. The time now is 02:25 AM.

Main Menu
Write for LQ is looking for people interested in writing Editorials, Articles, Reviews, and more. If you'd like to contribute content, let us know.
Main Menu
RSS1  Latest Threads
RSS1  LQ News
Twitter: @linuxquestions
Facebook: linuxquestions Google+: linuxquestions
Open Source Consulting | Domain Registration