Subject: Re: netmask/broadcast questions
To: SamMaEl <rimsky@teleport.com>
From: Robert Nestor <rnestor@metronet.com>
List: port-mac68k
Date: 12/30/1997 18:59:39
SamMaEl <rimsky@teleport.com> wrote:
> In my struggle to get ipnat working CORRECTLY on my subnet, I
>changed my local IP setup from:
>
>IPs 10.0.0.* # with 1-4 being used
>netmask 255.255.255.0 # which Bob Nestor pointed out as wrong
>broadcast 255.255.255.10 # also wrong?
>
I think what I wrote was that it didn't look correct to me. I could be
wrong, in fact I'm usually wrong more than I'm right.
> My new setup is:
>
>IPs 192.168.1.* # with 1-4 being used
>netmask 255.255.255.0 # which for a class C subnet SHOULD be right?
>broadcast 255.255.255.192 # ?? no clue on this one...
This still doesn't look correct to me. I think the Broadcast address
should be 192.168.1.255 for this setup, at least that's what it is on my
system using the same setup as you're now running. My understanding is
that the Broadcast address is basically (in C code):
Broadcast_address = (IP_address & netmask) | ~netmask;
-bob