North American Network Operators Group

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RE: 240/4

  • From: michael.dillon
  • Date: Wed Oct 17 22:56:57 2007

> > bureaucratic roadblock. ARIN's failure to allocate 240/4 space to 
> > THOSE WHO DESIRE IT is a bureaucratic roadblock. IETF's failure to 
> > un-reserve
> > 240/4 space is a bureaucratic roadblock.
> If you use this stuff internally and don't tell anybody about 
> it and nobody ever know, you're fine. You do not need IANA, 
> ARIN nor IETF permission to do that.

There you go, putting another roadblock in people's way. Now they have
to hack Cisco's and Microsoft's code to install their own patches. It
would be a heck of a lot more efficient for the IETF to approve use of
240/4 so that vendors add support for it, and the RIRs allocate it to
those who want it.

> I suggest respectfully you re-read Randy's initial email. If 
> you release
> 240/4 as public space, there are transitive issues. I care 
> about having one Internet, so this matters.

Anybody who buys into this argument is living in cloud cuckoo land.
There is no "ONE" Internet and probably never has been since UUNet
started in the TCP/IP networking business.

I know companies who use 1/8 through 8/8, and 126/8 for internal
networks. In one cases there are multiple networks using 1/8 and they
all interconnect through various layered NAT schemes. You think
double-NAT is bad?

All organizations that use IPv4 technology for any purpose, on or OFF
the Internet, are eligible to go to an RIR and get globally unique
addresses. Their harebrained networks impact your supply of IPv4
addresses. If you can get some of them to use globally unique addresses
from 240/4 that you don't want to use, then it is to your benefit
because your supply is bigger than it would have been.

Please don't try to engineer other people's networks because they are
not going to listen to you. It is a fact that 240/4 addresses work fine
except for one line of code in IOS, MS-Windows, Linux, BSD, that
explicitly disallows packets with this address. People have already
provided patches for Linux and BSD so that 240/4 addresses work
normally. Cisco would fix IOS if the IETF would unreserve these
addresses, and likely MS would follow suit, especially after Cisco makes
their changes.

This is a trivial engineering challenge. Admittedly there is an
interesting project management challenge in making sure that whatever
network wants to use these does not have a rogue box filtering the
traffic, but I'm not aware of any networking project that was not
challenging to project managers.

> > This is ridiculous and untrue. There is no evidence that 240/4 
> > addresses will blow up anything.
> > A while back people reported on the NANOG list what 
> happened when they 
> > tried to use them. Short answer, nothing happened.
> This is not my recollection. I, and others, tried it on many 
> platforms and it did not work. Try it again on a windows XP box.

"Not work" is nowhere near "blow up". 

> This is not enough to put it safely into production. All 
> equipment & software will have to be tested and certified. 
> This takes time & energy.

And is done routinely and regularly when a patch set is released.

--Michael Dillon