all zeroes/all ones used in host IP's...

[H. Peter Anvin]

Magnus Danielson wrote:
> 
> From: hpa en transmeta.com (H. Peter Anvin)
> Subject: Re: all zeroes/all ones used in host IP's...
> Date: 28 Jan 2000 11:55:20 -0800
> 
> > You are, indeed, completely wrong.  There rules are that neither the
> > *entire* network portion or the *entire* host portion of the address
> > can be all 0 or all 1.
> 
> No, he is correct if you go by RFC 1122. However, if you are running CIDR you
> are right. It seems most posts on this topic actually misses the pre/post CIDR
> conditions and you really have to read the full section of RFC 1122 and think
> of what class the address at hand has in order to fully interprent the
> paragraph that he quoted correctly.
> 

No, he's not; he claimed there was something magic about each *octet*. 
That has never been true, although people have, in the past, been keen
on putting the barriers at octet boundaries.

However, RFC 1122 is obsolete.  Everyone uses CIDR these days, and once
you have that, you have the rules I gave.  CIDR is Best Current Practice
per RFC 2050.

	-hpa

-- 
<hpa en transmeta.com> at work, <hpa en zytor.com> in private!
"Unix gives you enough rope to shoot yourself in the foot."

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