Fw: Re: Network Address/Netmask Notation

[David A. Bandel]

On Tue, 25 Mar 2003 22:10:54 -0800 (PST)
Keith Morse <kgmorse at mpcu.com> wrote:

> On Sun, 23 Mar 2003, David A. Bandel wrote:
> 
> > With non-VLSM CIDR, we can't use /#.  We will also get very large
> > headaches trying to calculate which IPs are found on a network with
> > absurd netmasks like 255.255.255.123.  If you don't think this is
> > valid, you can try it on your network and see that it works just
> > fine with the following values:
> > network: 192.168.0.1
> > netmask: 255.255.255.123
> > broadcast: 192.168.0.133
> > hosts:  192.168.0.5, 192.168.0.129
> > yes, for this particular netmask, there are only 2 hosts, other
> > non-VLSM netmasks give varying numbers of hosts in different
> > patterns scattered about between the network and broadcast numbers.
> 
> 
> Wild, I've never seen non-contigous netmasks before.  Is this legal
> per the ip specifiation, or just the result of the xor/nor (sorry
> don't remember the boolean operation involved between ip and netmask)
> operation?

This is 100% in accordance with the RFCs (not sure which one(s), perhaps
1518 and/or 1519).  Been a while since I actually read them.  And it's
AND for IP/Netmask.

Ciao,

David A. Bandel
-- 
Focus on the dream, not the competition.
		Nemesis Racing Team motto
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