Re: Discovering network subnets

From: Craig Holmes (leusent@link-net.org)
Date: Sun Aug 21 2005 - 02:10:23 EDT


On Saturday 20 August 2005 07:07, hannibal blog wrote:
> I'm not sure the network is a C class one, but I'm surprised that such
> an ip adress is an host IP.
AFAIK, in the most strict and archaic IP address scheme (depending on the
first octet) this could NOT be a usable host. This is because in a /24
x.x.x.0 is considered a wire address and/or broadcast address for the subnet.

In reality today, some administrators use the first and last IP address
anyway. In rarely breaks any network functionality and it's use is actually
specified in an RFC #(I don't know off the top of my head). Blame it on the
(so-called) shortage of IPv4 addresses.

So long story short, just because that IP is in use doesn't mean that subnet
ISN'T a /24.

Craig

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