APNIC returning 223/8 to IANA

Fri Mar 21 17:11:47 UTC 2003

> 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 bdragon at gweep.net 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.

Nope, we weren't talking about subnets, but the classful networks
themselves.

Would you agree, as I've suggested, that there is no inherent technical
limitation to using 223.255.255.0/24?