240/4

Thu Oct 18 18:53:49 UTC 2007

On Thu, 18 Oct 2007, Stephen Wilcox wrote:

>> You get a D on those facts because you did not review the "literature",
>> did not attempt reasonable coverage of the problem space, and did not
>> investigate whether or not there were other versions of the software
>> that have been patched to support 240/4.
>
> step awaaaay from the crack pipe...

I almost wrote a message similar to Joe's (actually did, and then canceled 
it).  I think (realy hope) that there's a misunderstanding here about 
exactly what 240/4 space would be used for.

I think Michael's point is that it can be allocated as "unique space for 
internal use".  i.e. kind of like 1918 space, but you know your slice of 
240/4 is only used on your network[1].  For that purpose, it's fine, as 
long as you determine that all your gear allows it.

If anyone really thinks it can be announced into the global routing table 
and expected to function, I'm afraid they've swallowed the crack pipe so 
far down that this thread is pointless for them.  Too many devices will 
never (can never[2]) be upgraded and are unlikely to go away in the 
forseeable future.  You just can't expect 240/4 (regardless of how trivial 
the code change would be) to ever work as globally & reliably as people 
expect the internet to work.

I could see bits of 240/4 perhaps being of use to large cable companies 
for whom there just isn't enough 1918 space to address all their CPE 
gear...and/or they really want unique addressing so that if/when networks 
merge IP conflicts are avoided.

1) As much as this can ever be known...you can't stop random IP squatters 
from picking random IP space out of their hats for use as "private" 
networks behind NAT.  Eventually, they realize some bit of the internet is 
unreachable...because it's their LAN.  The various squatters using 1/8 and 
the other "not-yet-allocated" /8s will all get the rude awakenings they 
deserve in time.

2) Anyone care to guess how much network gear is deployed that either 
won't or can't be upgraded?  i.e. Old cisco gear without the RAM and/or 
flash to handle a newer code train...the old one in use long since 
unsupported, or gear from vendors that no longer exist?  As long as this 
stuff generally works, nobody's likely to replace it.

----------------------------------------------------------------------
  Jon Lewis                   |  I route
  Senior Network Engineer     |  therefore you are
  Atlantic Net                |
_________ http://www.lewis.org/~jlewis/pgp for PGP public key_________