255 is forbidden because it's the broadcast address. As to 0 being
forbidden, uhm.. I think that's only as the last octet in a host
sequence. Why? My nameserver is at 209.161.0.2 and 209.161.0.3
Whatever 1123 says .0 seems to have been accepted in a network mask
sense, but I would doubt that as a last octet of a host it would not
work.
IE
209.161.0.0/32 (Host) is illegal
209.161.0.1/32 (Host) is legal
209.161.0.0/24 (Network) is legal
-- Michael Loftis ICQ: 15648280 AIM: DyJailBait Funny quip of the moment just happens to be.... Linux is like a tent: no gates, no windows, and an Apache inside!-----Original Message----- From: "Mike A. Harris" <mharris@meteng.on.ca> Date: Fri, 28 Jan 2000 12:44:51 -0500 (EST) Subject: all zeroes/all ones used in host IP's...
> On another mailing list I'm on there is a small discussion about > using "0's" in IP addresses. Nobody could categorically say > wether or not they are allowed or not including myself, so I > hunted down RFC 1123, and found the relevant section. > > Here it is: > > IP addresses are not permitted to have the value 0 or -1 > for > any of the <Host-number>, <Network-number>, or <Subnet- > number> fields (except in the special cases listed > above). > This implies that each of these fields will be at least > two > bits long. > > Now I interpreted that as meaning that none of the octets in an > IP address could be 0 or "-1" in either the network/subnet or > host portions of a valid host IP. The definition of "-1" is "all > ones" in the host or network/subnet portion. > > I interpret the above as meaning that it is not legal to have a > network like this: > > 192.168.0.0/24 or 23.0.0.0/24 > > with hosts 192.168.0.1 through 192.168.0.254 or with hosts > 23.0.0.1 through 23.0.0.254. > > The first zero makes it illegal no? Could someone in the know > please clarify this as it has been bugging me for some time and > nobody else seems to be able to say with 100% certainty what the > proper rule is. Also, would a network like: > > 142.255.255.0/24 be illegal? > > Someone has suggested that my interpretation is wrong, and if > that is indeed so, I'd like to know the proper interpretation and > share it with everyone. > > I looked through some of the kernel source and couldn't find any > special handling of such addresses. > > Thanks very much in advance. > Take care! > TTYL > > -- > Mike A. Harris Linux advocate > Computer Consultant GNU advocate > Capslock Consulting Open Source advocate > > Join the FreeMWare project - the goal to produce a FREE program in > which you can run Windows 95/98/NT, and other operating systems. > > http://www.freemware.org > > > - > To unsubscribe from this list: send the line "unsubscribe > linux-kernel" in > the body of a message to majordomo@vger.rutgers.edu > Please read the FAQ at http://www.tux.org/lkml/
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