all [0s|1]'s subnets

Tue Oct 8 17:42:57 UTC 1996

On Tue, 8 Oct 1996, Curtis Villamizar wrote:

> You can't us an all zeros or all ones host part.  That means that if

[...]

> The answer is it is absolutely legal to use all ones or all zeros in
> an octet of the network part.  There used to be some broken software
> that gave you trouble due to remnants of "address class" based code.
> That broken software should by now be long gone.

Hmmm...What if you have, say, 192.168.2.0/23. So the net address is
192.168.2.0 and the broadcast is 192.168.3.255. You should then be able to
use any address in between those, right? Like 192.168.2.255 and
192.168.3.0?

Both FreeBSD and BSDI appear to choke on those two addresses. Traceroute
from boxes with a default route do not even get to the router (which
does have classless forwarding enabled, BTW). Interestingly enough, an
address like 172.16.3.0 does make it to the router, leading me to believe
that there is still some classful kruft hanging around.

-BD