[AusNOG] Unadvertised large IPv4 allocations in the APNIC region

[Daniel Mills]

Hey Julien,

That is quite interesting. I know of a government organisation here in
Perth who has 2x /16's and are only advertising 1x /24 out of one of the
/16's and use the rest of that /16 for internal NAT ip addressing... An
extreme misuse im sure.

The other /16 of IPv4 space just sits on their BGP routes and is not used
at all.

How many other networks out there do the same? Im pretty sure there is
ISP's out there thinking that IPv4 addresses are better than IPv6 and have
'applied for more' because they are running out, just for the sake of it,
so that they have more when they might need it in a few years maybe.

Daniel Mills
Select Comms

On Thu, 21 Oct 2010 23:16:09 +1100, Julien Goodwin
<ausnog at studio442.com.au>
wrote:
> Just a little experiment, but hopefully of some interest to people here.
> 
> The full post is on livejournal, but the first few paragraphs are below.
> 
> http://laptop006.livejournal.com/52380.html
> 
> A few days ago I wondered how many of the large (/16 through /9)[1][2]
> IPv4 allocations were laying unused.
> 
> Armed with a copy of the APNIC whois data (An old one from the end of
> March this year) that I had lying around on my laptop, and a fresh dump
> of BGP routes from one of my border routers[3] (Monday night) I set to
> work.
> 
> From the whois DB I extracted 2,666 allocations, but as I've done no
> hand-verification there could be justified reasons for some of the
> unused routes. In at least one case it appears the blocks may since have
> been handed back, although given the size of the block in question (it's
> the /9 that's unannounced) I'd have expected at least some noise on one
> of the ops or RIR lists. Given the age of the DB any new allocations are
> most likely announced by now removing one source of error.
> 
> Then I simply matched my list of known allocations against the BGP
> tables looking for *any* route of that prefix, or longer (Valid source
> of error here if multiple contiguous blocks announced as a supernet, we
> often do this at work with a few of our /23's that were originally
> allocated as a pair of /24's). There's another issue that as *any* route
> is enough for me even a single /24 is enough for me to consider an
> entire /9 "in use".
> 
> Overall the allocations are very highly advertised, with only 13.5% of
> allocations unadvertised completely (on the public Internet, it's
> impossible to know how many may actually be in use behind NAT's).
> Converted into individual address that drops to 7.8%, much better then
> the Internet as a whole which sees roughly 38%[4] of allocations
> unadvertised. My numbers are so good for two reasons, first the
> aforementioned use of a single route (potentially a /24) to be enough
> for even a /9; second, as these blocks are larger they're far more
> likely to be assigned to people more serious about their networks, and
> even if they went out of business their network was likely sold as an
> asset.
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-- 
Kind Regards,

Daniel Mills
DIRECTOR

Select Communications (Australia) Pty Ltd

PHONE: +61 8 6365 5618
FAX: +61 8 6365 5619
EMAIL: daniel.mills at selectcorp.com.au

-- 
Kind Regards,

Daniel Mills
DIRECTOR

Select Communications (Australia) Pty Ltd

PHONE: +61 8 6365 5618
FAX: +61 8 6365 5619
EMAIL: daniel.mills at selectcorp.com.au