[OT-mask]

[Robert Brockway]

On Tue, 24 Feb 2004, James Knott wrote:

> > 68.95.134.255 resolves to:
> > adsl-68-95-134-255.dsl.rcsntx.swbell.net
>
> Perhaps I'm missing something here, but how does your example relate to
> your question?

I think what Gregory is asking is could the address listed here be a
normal host or it is definitely a broadcast address.  As per Ian's answer,
for any network larger than a /24 it is permissible to have host addresses
with the last byte being 255 [1].  The highest address in the subnet will
still be a broadcast address of course.

Consider the network 192.168.10/23.  This is a subnet containing 512 IPs
of which 510 are usable.

Now, we have:

Network address:	192.168.10.0
Broadcast address:	192.168.11.255
Long netmask:		255.255.254.0
Short netmask:		/23

The address 192.168.10.255 is a legitimate address for a host in this /23
network.

I've just paraphrased here as this was covered in my recent talk.  Those
who missed the talk but have an interest here are recommended to lookup
CIDR.  There are plenty of CIDR tutorials online.

Cheers,
	Rob

-- 
Robert Brockway
Senior Technical Consultant, OpenTrend Solutions Ltd.
Phone: 416-669-3073, Email: rbrockway-wgAaPJgzrDxH4x6Dk/4f9A at public.gmane.org, http://www.opentrend.net
OpenTrend Solutions: Reliable, secure solutions to real world problems.
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