[arin-ppml] ULA-C and reverse DNS

michael.dillon at bt.com michael.dillon at bt.com
Mon Mar 22 15:22:10 EDT 2010

> Permanent allocations are an absolutely horrible idea.  They 
> create a monotonically decreasing resource which cannot be 
> reclaimed when abandoned. Implementing such a thing reflects 
> a failure to learn from our IPv4 experience.

You are just playing semantic games. The meaning of a "permanent
allocation" will be defined by the global RIR policy. I fully
expect that policy to have some form of renewal process, and failure
to keep that up will cause the registrant to forfeit their block.
There will be some form of waiting period, perhaps 5 or 10 years,
after which the block is in play again, and might be snapped up
by a new registrant. Part of M&A due diligence will be to check the
status of any ULA-C blocks and if they are wholly unregistered 
or forfeited, then you know that you are dealing with incompetent
network administration. That kind of thing increases the risk of
merging networks therefore depressing the value of the company.
If forfeiture becomes at all common, then after a few instances
in which companies failed to get themselves bought, or sold at
bargain prices, with this as a factor, you'll start to see 
annual reports touting the fact that their IP addresses are
"in good standing" with the RIRs.

> s/ULA/GUA-tainted/g
> And you've got exactly the same scenario as ULA-C.

No. ULA-C addresses already exist and have been set aside
by IANA. There is currently no RFC or RIR policy defining
how they are used, so they are dormant. If you create
documents which use tainted GUA space for the same kind of
usage, then people will start to "pirate" the existing 
ULA-C space. That is not the same scenario.

ULA-C exists. Now we have to put some rules around it, and
some management practices.

> A liberal GUA policy which:
> 	1.	Does not assume prefixes will be routed
> 	2.	Offers the user a choice of "tainted prefixes" 
> if they choose
> 	3.	Is coupled with a modest fee structure (much more modest
> 		than the current fee structure, on the order of 
> $300 initial
> 		and $50 annual, for example)
> Would offer pretty much all that is good about ULA-C without 
> making it a tool for end-running addressing policy.


We have a small problem over here in the corner, dealing with
something analogous to private network addresses in IPv4, and
mainly concerning enterprise network architects. The solution
to that is *NOT* to change the rules for everybody, but to tidy
up the corner and make sure that it stays in the corner.

--Michael Dillon

More information about the ARIN-PPML mailing list