[mdlug] IPCOP install

[Thomas Cameron (Red Hat)]

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Sure you can!  You can subnet or supernet all you like as long as you
have control over the network.

For instance, if I want to supernet - make a standard class C-ish
network larger - I can twiddle the netmask like so:

192.168.0.0/255.255.254.0

That gives me a network which starts at 192.168.0.0 and ends at
192.168.1.255, or 512 addresses.  Perfectly legal.

More common example...  If I wanted to use only a small portion of a
large class A-ish network like 10.0.0.0 (which would "normally" have a
255.0.0.0 subnet mask), I can do this:

10.20.50.0/255.255.255.128

This gives me a subnet which starts at 10.20.50.0 and ends at
10.20.50.127, or 128 total addresses.

The only time you can't do this is if you don't own the other bits of
the network you want to use.  So if your ISP issues you (for instance)
24.55.122.8/255.255.255.248, that would give you 24.55.122.8 through
24.55.122.15.  You could not arbitrarily decide to use 255.255.255.240
and start using 16 addresses, since the ISP didn't assign them to you.
In reality, even if you did try that their router would probably not
allow it anyway, but you get the picture.

Google CIDR and read
http://en.wikipedia.org/wiki/Classless_Inter-Domain_Routing for some
really cool info on how subnet masks are used to do routing and
sub/supernetting.

Tony Bemus wrote:
| I believe you can not because the 192.168.x.x ip range is a Class C
| range with a default subnet mask of 255.255.255.0.  If you need to use
| the 255.255.0.0 subnet then start with a class B address like
| 172.16.x.x
|
| Tony Bemus
|
|
| On Tue, 2008-02-19 at 12:49 -0800, David Lane wrote:
|
|> Can you use 192.168.x.x and mask 255.255.0.0?
|>
|> David
|>
|
|
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| mdlug mailing list
| mdlug at mdlug.org
| http://mdlug.org/mailman/listinfo/mdlug


- --
Thomas Cameron, RHCE, RHCX, CNE, MCSE, MCT
Solutions Architect Team Lead, Central Region
512-241-0774 office / 512-585-5631 cell / 512-857-1345 fax

Red Hat rated #1 in value by CIOs for four years running:
http://www.redhat.com/about/news/prarchive/2007/CIO_Insight_Study.html
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