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

[Riley Williams]

Hi David.

First, can I state that this whole discussion relates specifically to
IPv4 and comments referring to IPv6 are meaningless and will be
ignored.

 >>  1. The relevant standard states that all IP addresses are
 >>     classified as one of classes A, B, C or D depending only
 >>     on the FIRST octet/byte thereof, as follows:
 >>
 >>	0		Reserved
 >>	1-127		Class A		 8 bit
 >>	128-191		Class B		16 bit
 >>	192-223		Class C		24 bit
 >>	224-254		Class D
 >>	255		Reserved

 > Not anymore. You can no longer determine the number of bits in
 > the network versus host part of an IP address just by looking at
 > the first octet. That's the piece of information missing.

Can I suggest that you re-read my comments, since I never made the
claim that you appear to be correcting in the first place.

If you check, you will note that I stated that the number of bits
listed above are those in the CLASS MASK, which is still true as far
as I am aware.

In addition, there is a requirement that the NETMASK must include AT
LEAST as many bits as are allocated to the appropriate class mask.

What is generally referred to as the "Netmask" nowadays is the mask
that combines the "Network number" and "Subnet number" fields that
Mike referred to in his posting.

Best wishes from Riley.

 * Copyright (C) 1999, Memory Alpha Systems.
 * All rights and wrongs reserved.

+----------------------------------------------------------------------+
| There is something frustrating about the quality and speed of Linux  |
| development, ie., the quality is too high and the speed is too high, |
| in other words, I can implement this XXXX feature, but I bet someone |
| else has already done so and is just about to release their patch.   |
+----------------------------------------------------------------------+
 * http://www.memalpha.cx/Linux/Kernel/


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