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North American Network Operators Group Date Prev | Date Next | Date Index | Thread Index | Author Index | Historical Re: APNIC returning 223/8 to IANA
I think your getting confused? The restriction is on subnets using classful addresses, you shouldnt use all zeros and all ones subnet for a given subnetted classful network. In the examples below, 192.0.0.0 and 192.0.255.0 are valid Class C networks.. however if you then go classless and presumably enable ip subnet-zero on your cisco routers as well then no such restrictions exist including on 1.0.0.0/24 or 223.255.255.255.0/24. On Thu, 20 Mar 2003 [email protected] wrote: > > > Its not quite that simple folks. The reason this particular > > block is reserved has some real technical merit, while the 69/8 > > muddle is strictly due to ISP negligence. > > > > RFC 3330 got it wrong. Anyone remember the "Martian List" > > from the 1970-1990's? Trying to use the all-ones or all-zeros > > network for real traffic is not possible. Pre CIDR it was > > not possible to use 192.0.0.0/24 or 192.0.255.0/24. (the same was > > true on -every- network boundary) With CIDR, > > those boundaries moved to 1.0.0.0/24 and 223.255.255.0/24 > > e.g. only two reservered blocks instead of hundreds. > > > > Simply having someonechange a DB entry or create an RFC will > > not affect the installed silicon base. Won't work. > > APNIC is on the moral highground here. They received damaged > > goods without notification. IANA needs better technical clue. > > > > --bill > > Unless I'm mistaken, there is no technical issue with using the > All-0's or All-1's classful networks. In fact, several of those networks > are in use. > > 0.0.0.0/8 "this" network (all-zeros A) > 127.0.0.0/8 loopback network (all-ones A) > 128.0.0.0/16 reserved but unused (all-zeros B) > 191.255.0.0/16 reserved but unused (all-ones B) > 192.0.0.0/24 reserved but unused (all-zeros C) > 223.255.255.0/24 reserved but unused (all-ones C) > > As with 0/8 and 127/8, the other 4 networks could certainly be > designated for some use, including "normal" end-users. This type of > end-user usage would even continue to work with old classful gear. > >
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