In message <v6909j20es.fsf@kechara.flame.org>Michael Graff writes
>Olaf Seibert <rhialto@polder.ubc.kun.nl> writes:
>
>> Yes, but host 0 still means "this host" or "unknown host" doesn't it? So
>> it would still not be a valid host address.
>
>0.0.0.0 means "this host" often enough, but to my knowledge noone has
>been assigned a prefix where all the bits are 0 :)
>
>204.152.186.0 should be a legal host, though.

I looked around a bit, and found only this reference in RFC 1812:

    IP addresses are not permitted to have the value 0 or -1 for the
    <Host-number> or <Network-prefix> fields except in the special cases
    listed above.  This implies that each of these fields will be at
    least two bits long.

The "special classes listed above" are all zeros, and all zeros
only for the network portion of the address;  both are to be used
for configuring addresses.

I'd love to hear if there are more recent RFCs describing this;
it certainly seems like it'd be nice to be able to use those extra
addresses.

Kevin
kml@novell.com