More than 254 computers on a network?

Not that I need to do this, but if an IP address range only has 254 useable
addresses, (192.168.0.1 - 192.168.0.254)... How does an organisation with
more than 254 computers connect them to the network?

Cheers
John

"John" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Not that I need to do this, but if an IP address range only has 254
useable
> addresses, (192.168.0.1 - 192.168.0.254)... How does an organisation with
> more than 254 computers connect them to the network?

By having more subnets and using a router/bridge to allow them all to
communicate with each other. E.g:

192.168.0.x ]
] bridge
192.168.1.x ]

HTH
--
Rob

Using a NAT or nested NATs. Search for "NAT" and you'll see how.

Paul DS.

"John" <(E-Mail Removed)> wrote in message
news:(E-Mail Removed)...
> Not that I need to do this, but if an IP address range only has 254
> useable addresses, (192.168.0.1 - 192.168.0.254)... How does an
> organisation with more than 254 computers connect them to the network?

An IP address range in the private address space can have up to 16,777,214
useable addresses (10.0.0.1 - 10.255.255.254). You just use a different
network address and subnet mask.

Of course, it is unlikely to be practical to have anything like that number.
The solution is to use multiple networks with routers joining them
together - essentially the same as the entire Internet, but on a smaller
scale.

Bridges do not create multiple networks; the example Rob gave is valid but
will not (by itself) allow one set of machines to talk to the other,
assuming both sets use a subnet mask of 255.255.255.0.

The routers can perform NAT as Paul DS suggested, but this is usually
neither necessary nor desirable. It is necessary with some domestic routers,
which would probably not be suitable anyway.

Alex

> The routers can perform NAT as Paul DS suggested, but this is usually
> neither necessary nor desirable. It is necessary with some domestic
routers,
> which would probably not be suitable anyway.
>
> Alex
>

Alex is quite right. I read "connect them to the network" as "connect them
to the internet" however I would add that you cannot expose the private
address space to the outside world so you probably will require some
NAT-like function to allow all your internal machines to surf to the outside
without each having to have their own "real" IP address.

Paul DS.

On Tue, 10 May 2005 13:23:44 +0100, "Alex Fraser" <(E-Mail Removed)>
wrote:

>"John" <(E-Mail Removed)> wrote in message
>news:(E-Mail Removed)...
>> Not that I need to do this, but if an IP address range only has 254
>> useable addresses, (192.168.0.1 - 192.168.0.254)... How does an
>> organisation with more than 254 computers connect them to the network?
>An IP address range in the private address space can have up to 16,777,214
>useable addresses (10.0.0.1 - 10.255.255.254). You just use a different
>network address and subnet mask.

Yup - just to clarify for John, 192.168.x.x is not the only possible
IP range for internal networks.

RFC 1918 http://www.faqs.org/rfcs/rfc1918.html specifies the
following:

10.0.0.0 - 10.255.255.255 (16,387,064 addresses)
172.16.0.0 - 172.31.255.255 (1,032,256 addresses)
192.168.0.0 - 192.168.255.255 (254 addresses)

(The issue of whether 0 constitutes an addressable IP is contentious;
but for day-to-day use you are correct in presuming that it is not)

Alex and other people's comments about bridges, routers and NATs are
also correct. In addition to the 10. and 172.16. IP ranges, you can
also chain multiple smaller identically-addressed networks together
using Network Address Translation (NAT).

Most small internal networks use 192.168. and most large internal
networks, such as multinational corporates, use 10. I've only ever
seen a couple of 172.16. private networks.

--
Andrew Oakley andrew/atsymbol/aoakley/stop/com

In article <(E-Mail Removed)>, John says...
> Not that I need to do this, but if an IP address range only has 254 useable
> addresses, (192.168.0.1 - 192.168.0.254)... How does an organisation with
> more than 254 computers connect them to the network?
>
Use a subnet mask of 255.0.0.0 which will let you have 16 million IP
addresses.

www.learntosubnet.com


--
Conor

"Of all the things I've lost, I miss my mind the most." O.Osbourne.

In message <(E-Mail Removed)>, John
<(E-Mail Removed)> scribes
>Not that I need to do this, but if an IP address range only has 254 useable
>addresses, (192.168.0.1 - 192.168.0.254)... How does an organisation with
>more than 254 computers connect them to the network?
>
>Cheers
>John
>
>
Use network:-
192.168.0.0/23 (subnet mask 255.255.254.0) gives 512 with 510 usable
192.168.0.0/22 (subnet mask 255.255.252.0) etc, etc

At work we use 10.235.n.0/20 where n = 0 or 16 or 32 and so on.
--
Snowy

>
> 10.0.0.0 - 10.255.255.255 (16,387,064 addresses)
> 172.16.0.0 - 172.31.255.255 (1,032,256 addresses)
> 192.168.0.0 - 192.168.255.255 (254 addresses)
>

192.168.0.0 actually has 16382 addresses not 255. It is usually subnetted
down to 256 separate networks with 254 addresses in each but there is
nothing to stop you creating a network with 510 addresses e.g. 192.168.2.0
subnet mask 255.255.254.0 (23 bits) or 1022 addresses or 192.168.0.0
255.255.252.0 (22 bits) etc.

John Steele

On Tue, 10 May 2005 22:20:59 +0100, "John Steele"
<(E-Mail Removed)> wrote:
>> 10.0.0.0 - 10.255.255.255 (16,387,064 addresses)
>> 172.16.0.0 - 172.31.255.255 (1,032,256 addresses)
>> 192.168.0.0 - 192.168.255.255 (254 addresses)
>192.168.0.0 actually has 16382 addresses not 255. It is usually subnetted

Whoops. I really shouldn't have made that mistake, what with running
192.168.7.xxx (the free WiFi hotspot I run for my neighbours) and
192.168.0.xxx (my private LAN) in my very own house. Thanks.

http://www.nam-vets.org/frampton


--
Andrew Oakley andrew/atsymbol/aoakley/stop/com